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In this manuscript we provide computational support to the catalytic role of water in all kinds of pseudopericyclic reactions operating in the reductive acid cycle, as well as in other metabolic processes. Water catalysis is not limited to those reactions where simple translocation of hydrogen atoms occurs, such as those represented by NuH+E→Nu-EH general equation. Indeed, water catalysis is more general and extremely important in tautomerization reactions of the type HX-Y=Z→X=Y-ZH, which operate in the reductive citric acid cycle and metabolic processes. Moreover, the comprehensive theoretical study reported herein illustrates that these reactions appear to behave as authentic enzyme-catalyzed reactions showing Michaelis-Menten behavior, however with the abnormal singularity that the concentration of the catalytic "water clusters" of different length and nature must be taken as a huge number. Overall, the results presented are suggestive of the workability of the so-called "metabolism first" proposal in a hot water world, as water catalysis eliminates the dilution problem frequently associated to this proposal.
José M. Saá; Antonio Frontera. On the Role of Water as a Catalyst in Prebiotic Chemistry. ChemPhysChem 2020, 21, 313 -320.
AMA StyleJosé M. Saá, Antonio Frontera. On the Role of Water as a Catalyst in Prebiotic Chemistry. ChemPhysChem. 2020; 21 (4):313-320.
Chicago/Turabian StyleJosé M. Saá; Antonio Frontera. 2020. "On the Role of Water as a Catalyst in Prebiotic Chemistry." ChemPhysChem 21, no. 4: 313-320.
Catalyst-free and solvent-free reactions of the type NuH + E → Nu–EH are NuH-catalyzed processes in which Grotthuss-like proton shuttling pays a key role.
Victor J. Lillo; Javier Mansilla; Jose M. Saa. The role of proton shuttling mechanisms in solvent-free and catalyst-free acetalization reactions of imines. Organic & Biomolecular Chemistry 2018, 16, 4527 -4536.
AMA StyleVictor J. Lillo, Javier Mansilla, Jose M. Saa. The role of proton shuttling mechanisms in solvent-free and catalyst-free acetalization reactions of imines. Organic & Biomolecular Chemistry. 2018; 16 (24):4527-4536.
Chicago/Turabian StyleVictor J. Lillo; Javier Mansilla; Jose M. Saa. 2018. "The role of proton shuttling mechanisms in solvent-free and catalyst-free acetalization reactions of imines." Organic & Biomolecular Chemistry 16, no. 24: 4527-4536.
Organocatalysts displaying a network of cooperative hydrogen bonds (NCHB) have been employed in an enzyme-like manner for a direct, switchable synthesis of enantiopure hexahydropyrimidinones (HHPMs) or dihydropyrimidinones (DHPMs), which starts at a common, easily accessible α-ureidosulfone stage. The NCHB organocatalyst exploits all its potential as a pure hydrogen-bond biomimetic catalyst even in the presence of organic bases. This one-pot, diastereo- and enantioselective synthetic procedure has been proven to be robust, scalable, highly efficient, and environmentally benign. A straightforward and truly practical entry to enantiopure HHPMs is reported for the first time.
V. J. Lillo; Jose M. Saa; Victor Javier Lillo Dangla. Towards Enzyme-like, Sustainable Catalysis: Switchable, Highly Efficient Asymmetric Synthesis of Enantiopure Biginelli Dihydropyrimidinones or Hexahydropyrimidinones. Chemistry – A European Journal 2016, 22, 17182 -17186.
AMA StyleV. J. Lillo, Jose M. Saa, Victor Javier Lillo Dangla. Towards Enzyme-like, Sustainable Catalysis: Switchable, Highly Efficient Asymmetric Synthesis of Enantiopure Biginelli Dihydropyrimidinones or Hexahydropyrimidinones. Chemistry – A European Journal. 2016; 22 (48):17182-17186.
Chicago/Turabian StyleV. J. Lillo; Jose M. Saa; Victor Javier Lillo Dangla. 2016. "Towards Enzyme-like, Sustainable Catalysis: Switchable, Highly Efficient Asymmetric Synthesis of Enantiopure Biginelli Dihydropyrimidinones or Hexahydropyrimidinones." Chemistry – A European Journal 22, no. 48: 17182-17186.
Victor J. Lillo; Javier Mansilla; Jose M. Saa. ChemInform Abstract: Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. ChemInform 2016, 47, 1 .
AMA StyleVictor J. Lillo, Javier Mansilla, Jose M. Saa. ChemInform Abstract: Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. ChemInform. 2016; 47 (30):1.
Chicago/Turabian StyleVictor J. Lillo; Javier Mansilla; Jose M. Saa. 2016. "ChemInform Abstract: Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas." ChemInform 47, no. 30: 1.
The concept of noncovalent organocatalysis by means of networks of cooperative hydrogen bonds (NCHB organocatalysis) has been explored. Arylideneureas were chosen as ideal substrates because of their powerful donor–acceptor properties. We have examined their uncatalyzed, direct Mannich reaction with acetoacetates in comparison with that catalyzed by a number of salan derivatives capable of providing a network of cooperative hydrogen bonds. Catalyst D [(R,R)-N,N′-bis(salicyl)cyclohexane-1,2-diamine] was found to drive the above direct Mannich reaction in an enantioselective manner, thereby allowing the synthesis of several Biginelli dihydropyrimidinones with high enantioselectivity. DFT calculations (B3LYP-D-PCM/6-31+G*//B3LYP/6-31+G*) revealed that the NCHB organocatalyst lowers the energy barrier of the reaction. The NCHB organocatalysts appear to function as biomimetic catalysts.
Victor J. Lillo; Javier Mansilla; José M. Saá. Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. Angewandte Chemie 2016, 128, 4384 -4388.
AMA StyleVictor J. Lillo, Javier Mansilla, José M. Saá. Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. Angewandte Chemie. 2016; 128 (13):4384-4388.
Chicago/Turabian StyleVictor J. Lillo; Javier Mansilla; José M. Saá. 2016. "Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas." Angewandte Chemie 128, no. 13: 4384-4388.
The concept of noncovalent organocatalysis by means of networks of cooperative hydrogen bonds (NCHB organocatalysis) has been explored. Arylideneureas were chosen as ideal substrates because of their powerful donor–acceptor properties. We have examined their uncatalyzed, direct Mannich reaction with acetoacetates in comparison with that catalyzed by a number of salan derivatives capable of providing a network of cooperative hydrogen bonds. Catalyst D [(R,R)-N,N′-bis(salicyl)cyclohexane-1,2-diamine] was found to drive the above direct Mannich reaction in an enantioselective manner, thereby allowing the synthesis of several Biginelli dihydropyrimidinones with high enantioselectivity. DFT calculations (B3LYP-D-PCM/6-31+G*//B3LYP/6-31+G*) revealed that the NCHB organocatalyst lowers the energy barrier of the reaction. The NCHB organocatalysts appear to function as biomimetic catalysts.
Victor J. Lillo; Javier Mansilla; José M. Saá. Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. Angewandte Chemie International Edition 2016, 55, 4312 -4316.
AMA StyleVictor J. Lillo, Javier Mansilla, José M. Saá. Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas. Angewandte Chemie International Edition. 2016; 55 (13):4312-4316.
Chicago/Turabian StyleVictor J. Lillo; Javier Mansilla; José M. Saá. 2016. "Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas." Angewandte Chemie International Edition 55, no. 13: 4312-4316.
Extensive experimental and computational studies have been carried out on the enantioselective titanium(IV)-catalyzed cyanobenzoylation of aldehydes using 1:n Binolam:Ti(OiPr)4 mixtures as precatalysts, with the purpose of identifying the key mechanistic aspects governing enantioselectivity. HCN and isopropyl benzoate were detected in the reacting mixtures. This, as well as the reaction’s response to the presence of an exogenous base, and the failure to react in the presence of Binol:Ti(OiPr)4 mixtures, led us to propose not a direct cyanobenzoylation but an indirect process involving enantioselective hydrocyanation followed by O-benzoylation. Computational work provided positive evidence for the intervention of both indirect and direct cyanobenzoylation routes, the former being faster. However, the standard Curtin–Hammett-based optimization search ended with unsatisfactory results. Experimental and computational DFT studies (B3LYP/6-31G*) led us to conclude that: (1) the overall cyanobenzoylation of aldehydes catalyzed by 1:n Binolam:Ti(OiPr)4 mixtures involves an enantioselective hydrocyanation followed by an stereochemically inert O-benzoylation; (2) the initial complexes prevailing in a 1:1 Binolam:Ti(OiPr)4 mixture are the solvated mononuclear monomer 5·2(iPrOH) and solvated dinuclear dimer 9·2(iPrOH), whereas 9·2(iPrOH) is the major component in a 1:2 or higher 1:n mixture; (3) since the slowest step is that of benzoylation of ligated iPrOH which yields the actual catalysts 5–9, the catalytic system fits into a non-Curtin–Hammett framework, the final products deriving from a kinetic quench of the competing routes; and (4) accordingly, catalysis by 1:1 Binolam:Ti(OiPr)4 mixtures should involve cyanobenzoylations promoted by mononuclear 5, contaminated with those promoted by some dinuclear open dimer 9, whereas cyanobenzoylations catalyzed by a 1:2 and higher 1:n mixtures should be the result of catalysis promoted by the large amounts of dinuclear open dimer 9.
José M. Saá; Alejandro Baeza; Carmen Nájera; José M. Sansano. Curtin–Hammett versus non-Curtin–Hammett frameworks in optimizing the enantioselective binolam/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 2. Tetrahedron: Asymmetry 2011, 22, 1292 -1305.
AMA StyleJosé M. Saá, Alejandro Baeza, Carmen Nájera, José M. Sansano. Curtin–Hammett versus non-Curtin–Hammett frameworks in optimizing the enantioselective binolam/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 2. Tetrahedron: Asymmetry. 2011; 22 (12):1292-1305.
Chicago/Turabian StyleJosé M. Saá; Alejandro Baeza; Carmen Nájera; José M. Sansano. 2011. "Curtin–Hammett versus non-Curtin–Hammett frameworks in optimizing the enantioselective binolam/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 2." Tetrahedron: Asymmetry 22, no. 12: 1292-1305.
The enantioselective titanium(IV)-catalyzed cyanobenzoylation of aldehydes using 1:1 BINOLAM/Ti(OiPr)4 mixtures as a precatalyst gave O-aroyl cyanohydrins 4 with good enantiomeric excesses. The standard optimization set carried out on the assumption of Curtin–Hammett behavior, led to no amelioration. Extensive experimental and computational studies were carried out with the purpose of identifying the key mechanistic aspects governing enantioselectivity. HCN and isopropyl benzoate were detected in the reacting mixtures. This as well as the reaction response to the presence of an exogenous base, and the failure to react in the presence of Binol/Ti(OiPr)4 mixtures, led us to propose, not a direct but an indirect process involving an enantioselective hydrocyanation step followed by O-benzoylation. Computational work carried out with mononuclear monomeric MM and dinuclear mixed dimer DlMD as catalysts support this mechanistic proposal. On the other hand, cyanobenzoylations carried out with 1:2 or higher 1:n (up to 1:5) BINOLAM/Ti(OiPr)4 mixtures appear to involve a reversal of the enantioselection. This, together with the fact that the benzoylation of the ligated iPrOH is a slow reaction, has led us to conclude that these cyanobenzoylations do not fit within the standard Curtin–Hammett kinetic scheme. Instead, such BINOLAM/Ti(OiPr)4 -catalyzed cyanobenzoylations of aldehydes rather behave as non-Curtin–Hammett kinetic schemes. Further computational analysis is needed in order to make a clear distinction between Curtin–Hammett and non-Curtin–Hammett kinetic frameworks.
Alejandro Baeza; Carmen Nájera; José M. Sansano; José M. Saá. Mechanistic studies on the enantioselective BINOLAM/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 1. Tetrahedron: Asymmetry 2011, 22, 1282 -1291.
AMA StyleAlejandro Baeza, Carmen Nájera, José M. Sansano, José M. Saá. Mechanistic studies on the enantioselective BINOLAM/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 1. Tetrahedron: Asymmetry. 2011; 22 (12):1282-1291.
Chicago/Turabian StyleAlejandro Baeza; Carmen Nájera; José M. Sansano; José M. Saá. 2011. "Mechanistic studies on the enantioselective BINOLAM/titanium(IV)-catalyzed cyanobenzoylation of aldehydes: Part 1." Tetrahedron: Asymmetry 22, no. 12: 1282-1291.
Javier Mansilla; Jose M. Saa. ChemInform Abstract: Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues. ChemInform 2011, 42, 1 .
AMA StyleJavier Mansilla, Jose M. Saa. ChemInform Abstract: Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues. ChemInform. 2011; 42 (13):1.
Chicago/Turabian StyleJavier Mansilla; Jose M. Saa. 2011. "ChemInform Abstract: Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues." ChemInform 42, no. 13: 1.
The ligand 3,3'‐bis(diethylaminomethyl)‐1,1'‐bi‐2‐naphthol (binolam) contains an arrayed Brønsted acid–Brønsted base (BABB) system, which is responsible for the original shape of its lanthanide compounds. The solution structure of Pr, Nd and Yb compounds is solved by means of paramagnetic NMR spectroscopy and it is demonstrated that they are substantially isostructural, but with a completely new fold compared to the apparently similar heterobimetallic systems based on 1,1'‐bis(2‐naphthol) (binol) and alkali cations. The aromatic nuclei lie in a region equatorial with respect to the C3 symmetry axis, whereas the alkylamine chain stretches almost parallel to C3, above (and below) Ln3+. This is also found in the crystal structure of the binolamo–scandium complex. A detailed study of the proton‐exchange processes within the network of BABBs present in the complex is reported, which provides insight into the mechanism of the enantioselective Henry reaction promoted by these systems.
Lorenzo Di Bari; Sebastiano Di Pietro; Gennaro Pescitelli; Fernando Tur; Javier Mansilla; José M. Saá. [Ln(binolam)3]⋅(OTf)3, a New Class of Propeller-Shaped Lanthanide(III) Salt Complexes as Enantioselective Catalysts: Structure, Dynamics and Mechanistic Insight. Chemistry – A European Journal 2010, 16, 14190 -14201.
AMA StyleLorenzo Di Bari, Sebastiano Di Pietro, Gennaro Pescitelli, Fernando Tur, Javier Mansilla, José M. Saá. [Ln(binolam)3]⋅(OTf)3, a New Class of Propeller-Shaped Lanthanide(III) Salt Complexes as Enantioselective Catalysts: Structure, Dynamics and Mechanistic Insight. Chemistry – A European Journal. 2010; 16 (47):14190-14201.
Chicago/Turabian StyleLorenzo Di Bari; Sebastiano Di Pietro; Gennaro Pescitelli; Fernando Tur; Javier Mansilla; José M. Saá. 2010. "[Ln(binolam)3]⋅(OTf)3, a New Class of Propeller-Shaped Lanthanide(III) Salt Complexes as Enantioselective Catalysts: Structure, Dynamics and Mechanistic Insight." Chemistry – A European Journal 16, no. 47: 14190-14201.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
M. Paz; Carlos Saa; E. Guitian; L. Castedo; Jose M. Saa. ChemInform Abstract: Reactivity of Isoquinoline Alkaloids with Benzyne. ChemInform 2010, 24, 1 .
AMA StyleM. Paz, Carlos Saa, E. Guitian, L. Castedo, Jose M. Saa. ChemInform Abstract: Reactivity of Isoquinoline Alkaloids with Benzyne. ChemInform. 2010; 24 (37):1.
Chicago/Turabian StyleM. Paz; Carlos Saa; E. Guitian; L. Castedo; Jose M. Saa. 2010. "ChemInform Abstract: Reactivity of Isoquinoline Alkaloids with Benzyne." ChemInform 24, no. 37: 1.
For Abstract see ChemInform Abstract in Full Text.
Jesús Casas; Carmen Nájera; José M. Sansano; Jose M. Saa. ChemInform Abstract: BINOLAM, a Recoverable Chiral Ligand for Bifunctional Enantioselective Catalysis: The Asymmetric Synthesis of Cyanohydrins. ChemInform 2010, 33, no -no.
AMA StyleJesús Casas, Carmen Nájera, José M. Sansano, Jose M. Saa. ChemInform Abstract: BINOLAM, a Recoverable Chiral Ligand for Bifunctional Enantioselective Catalysis: The Asymmetric Synthesis of Cyanohydrins. ChemInform. 2010; 33 (48):no-no.
Chicago/Turabian StyleJesús Casas; Carmen Nájera; José M. Sansano; Jose M. Saa. 2010. "ChemInform Abstract: BINOLAM, a Recoverable Chiral Ligand for Bifunctional Enantioselective Catalysis: The Asymmetric Synthesis of Cyanohydrins." ChemInform 33, no. 48: no-no.
Conscious of the importance that stereochemical issues may have on the design of efficient organocatalyts for both Morita-Baylis-Hillman and aza-Morita-Baylis-Hillman reaction we have analyzed them in this minireview. The so-called standard reactions involve “naked” enolates which therefore should lead to the syn adducts as the major products, irrespective of the E, Z stereochemistry of the enolate. Accordingly, provided the second step is rate determining step, the design of successful bifunctional or polyfunctional catalysts has to consider the geometrical requirements imposed by the transition structures of the second step of these reactions. On the other hand, MBH and aza-MBH reactions co-catalyzed by (S)-proline and a secondary or tertiary amine (co-catalyst) involve the aldol-type condensation of either a 3-amino-substituted enamine, dienamine, or both, depending on the cases. A Zimmerman-Traxler mechanism defines the stereochemical issues regarding these co-catalyzed condensations which parallel those of the well established (S)-proline catalyzed aldol-like reactions.
Javier Mansilla; Jose M. Saa. Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues. Molecules 2010, 15, 709 -734.
AMA StyleJavier Mansilla, Jose M. Saa. Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues. Molecules. 2010; 15 (2):709-734.
Chicago/Turabian StyleJavier Mansilla; Jose M. Saa. 2010. "Enantioselective, Organocatalytic Morita-Baylis-Hillman and Aza-Morita-Baylis-Hillman Reactions: Stereochemical Issues." Molecules 15, no. 2: 709-734.
Shelf stable, chiral-at-metal, D(3) symmetric, 3:1 complexes of lanthanide (III) triflate salts are easily available by complexation with binolam (3,3'-diethylaminomethyl-2,2'-dihydroxy-1,1'-dinaphthalene) 1 or binolamo (3,3'-diethylaminooxymethyl-2,2'-dihydroxy-1,1'-dinaphthalene) 2 ligands. The resulting compounds 3Ln and 4Ln are isostructural, as demonstrated by their spectroscopic data, and possess an arrayed acid-base LABABB network. Complexes are kinetically labile, and in solution undergo hydrolysis by water. The lanthanum complex derived from binolam, i.e., (Delta,S,S,S)- (binolam)(3).la(OTf)(3)3La was found to be the most active catalyst in promoting direct nitroaldol reactions upon aldehydes and trifluoromethyl ketones, thereby giving rise to secondary nitroalcohols and tertiary alpha-trifluoromethyl-beta-nitroalcohols, respectively, with high ee in both cases. Enantiomerically enriched tertiary nitroalcohols were easily reduced to the corresponding aminoalcohols having a quaternary asymmetric carbon without loss of enantiomeric purity.
José M. Saá; Fernando Tur; José González. Lanthanide (III) salt complexes: Arrayed acid-base networks for enantioselective catalysis. The nitroaldol reaction upon aldehydes and trifluoromethylketones. Chirality 2009, 21, 836 -842.
AMA StyleJosé M. Saá, Fernando Tur, José González. Lanthanide (III) salt complexes: Arrayed acid-base networks for enantioselective catalysis. The nitroaldol reaction upon aldehydes and trifluoromethylketones. Chirality. 2009; 21 (9):836-842.
Chicago/Turabian StyleJosé M. Saá; Fernando Tur; José González. 2009. "Lanthanide (III) salt complexes: Arrayed acid-base networks for enantioselective catalysis. The nitroaldol reaction upon aldehydes and trifluoromethylketones." Chirality 21, no. 9: 836-842.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Carmen Nájera; José M. Sansano; José M. Saá. ChemInform Abstract: Bifunctional Binols: Chiral 3,3′-Bis(aminomethyl)-1,1′-bi-2-naphthols (Binolams) in Asymmetric Catalysis. ChemInform 2009, 40, 1 .
AMA StyleCarmen Nájera, José M. Sansano, José M. Saá. ChemInform Abstract: Bifunctional Binols: Chiral 3,3′-Bis(aminomethyl)-1,1′-bi-2-naphthols (Binolams) in Asymmetric Catalysis. ChemInform. 2009; 40 (32):1.
Chicago/Turabian StyleCarmen Nájera; José M. Sansano; José M. Saá. 2009. "ChemInform Abstract: Bifunctional Binols: Chiral 3,3′-Bis(aminomethyl)-1,1′-bi-2-naphthols (Binolams) in Asymmetric Catalysis." ChemInform 40, no. 32: 1.
3,3′‐Bis(dialkylaminomethyl)‐1,1′‐binaphth‐2‐ols (Binolams) have emerged during the last five years as very efficient chiral ligands in many enantioselective processes. Enantiomerically pure Binolams are easily accessible by means of a variety of methods, the most widely used being the so‐called chiral Binol route. In most cases, Binolam‐metal complexes behave as bifunctional catalysts: that is, they are characterized by their dual action on the reagents, being able to activate both the nucleophilic and the electrophilic species involved in the reaction. The most successful transformations carried out with complexes of this type include cyanation of aldehydes and ketones and enantioselective nucleophilic additions of enolate derivatives and organometallic compounds to C=O or C=N double bonds. As a final bonus, the basic natures of these ligands allow their recovery in high yields in numerous transformations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Carmen Nájera; José M. Sansano; José M. Saá. Bifunctional Binols: Chiral 3,3′‐Bis(aminomethyl)‐1,1′‐bi‐2‐naphthols (Binolams) in Asymmetric Catalysis. European Journal of Organic Chemistry 2009, 2009, 2385 -2400.
AMA StyleCarmen Nájera, José M. Sansano, José M. Saá. Bifunctional Binols: Chiral 3,3′‐Bis(aminomethyl)‐1,1′‐bi‐2‐naphthols (Binolams) in Asymmetric Catalysis. European Journal of Organic Chemistry. 2009; 2009 (15):2385-2400.
Chicago/Turabian StyleCarmen Nájera; José M. Sansano; José M. Saá. 2009. "Bifunctional Binols: Chiral 3,3′‐Bis(aminomethyl)‐1,1′‐bi‐2‐naphthols (Binolams) in Asymmetric Catalysis." European Journal of Organic Chemistry 2009, no. 15: 2385-2400.
Predictions (DFT/B3LYP calculations) are that cyclopentadienyl lithium edge‐fused to [n]circulenes in a circum‐like manner should self‐assemble as rod‐like, nanometer long, supersandwich compounds (see figure). On the contrary, triazolyl lithium analogues prefer to dimerize thereby giving rise to shell‐like dimers of variable curvatures. This study is aimed at exploring M. Etter's (T. W. Panunto, Z. Urbanczyk‐Lipkowska, R. Jonhson, M. Etter, J. Am. Chem. Soc. 1987, 109, 7786–7797) bottom‐up approach towards the design of organic‐solid sate materials. Guided by the electrostatic paste (“gluing”) effect of lithium, we examined the self‐assembly modes of a series of cyclopentadienyl lithium edge‐fused to benzene, as well as to [n]circulenes, arranged in a circum‐like manner by means of DFT/B3 LYP calculations. We have also examined the self‐assembly modes of the analogous triazolyl derivatives. Generally, well defined trends have been found. Thus, whereas cylcopentadienyl derivatives 1, 3 and 5 tend to aggregate as rod‐like, nanometer‐long, supersandwich compounds, the corresponding triazolyl analogues 2, 4 and 6 tend to dimerize thus giving rise to shell‐like dimers of variable curvatures. In our view, M. Etter's bottom‐up approach combined with high level calculations appears to have great potential for designing complex molecular architectures and nanostructures. Hopefully, these studies will spur the activity of synthetic and materials chemists.
José M. Saá; Manuel Yanez. On the “Gluing” Effect of Lithium: The Lithium-Driven Assembly of Circum-Arranged, Edge-Fused Cyclopentadienyl Lithium Compounds and Aza Analogues. Chemistry – A European Journal 2009, 15, 3123 -3129.
AMA StyleJosé M. Saá, Manuel Yanez. On the “Gluing” Effect of Lithium: The Lithium-Driven Assembly of Circum-Arranged, Edge-Fused Cyclopentadienyl Lithium Compounds and Aza Analogues. Chemistry – A European Journal. 2009; 15 (13):3123-3129.
Chicago/Turabian StyleJosé M. Saá; Manuel Yanez. 2009. "On the “Gluing” Effect of Lithium: The Lithium-Driven Assembly of Circum-Arranged, Edge-Fused Cyclopentadienyl Lithium Compounds and Aza Analogues." Chemistry – A European Journal 15, no. 13: 3123-3129.
Fernando Tur; Jose M. Saa. ChemInform Abstract: Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons. ChemInform 2008, 39, 1 .
AMA StyleFernando Tur, Jose M. Saa. ChemInform Abstract: Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons. ChemInform. 2008; 39 (16):1.
Chicago/Turabian StyleFernando Tur; Jose M. Saa. 2008. "ChemInform Abstract: Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons." ChemInform 39, no. 16: 1.
Herein we describe the first direct, catalytic enantioselective nitroaldol (Henry) reaction of simple α-trifluoromethyl ketones with nitromethane using a chiral monometallic lanthanum(III) triflate salt complex, namely [(Δ,S,S,S)-Binolam]3·La(OTf)3, as enantioselective catalyst. The resulting α-trifluoromethyl tertiary nitroaldols were obtained in moderate to high yields (up to 93%) and enantioselectivities (up to 98% ee). These adducts are versatile chiral building blocks and may be reduced (NiCl2/NaBH4) to their β-amino-α-trifluoromethyl tertiary alcohols without loss of enantiomeric purity.
Fernando Tur; José M. Saá. Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons. Organic Letters 2007, 9, 5079 -5082.
AMA StyleFernando Tur, José M. Saá. Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons. Organic Letters. 2007; 9 (24):5079-5082.
Chicago/Turabian StyleFernando Tur; José M. Saá. 2007. "Direct, Catalytic Enantioselective Nitroaldol (Henry) Reaction of Trifluoromethyl Ketones: An Asymmetric Entry to α-Trifluoromethyl-Substituted Quaternary Carbons." Organic Letters 9, no. 24: 5079-5082.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Alejandro Baeza; José M. Sansano; José M. Saá; Carmen Nájera. Enantioenriched Cyanohydrin O-Phosphates: Synthesis and Applications as Chiral Building Blocks. ChemInform 2007, 38, 1 .
AMA StyleAlejandro Baeza, José M. Sansano, José M. Saá, Carmen Nájera. Enantioenriched Cyanohydrin O-Phosphates: Synthesis and Applications as Chiral Building Blocks. ChemInform. 2007; 38 (29):1.
Chicago/Turabian StyleAlejandro Baeza; José M. Sansano; José M. Saá; Carmen Nájera. 2007. "Enantioenriched Cyanohydrin O-Phosphates: Synthesis and Applications as Chiral Building Blocks." ChemInform 38, no. 29: 1.