The conversion of carbon dioxide (CO 2 ), an abundant renewable carbon reagent, into chemicals of academic and industrial interest is of imminent importance to create a higher degree of sustainability in chemical processing and production.
19 September 2018 in Angewandte Chemie International Edition
The first asymmetric synthesis of α,α-disubstituted allylic N-arylamines based on a palladium-catalyzed allylic amination has been developed. The protocol uses highly modular vinyl cyclic carbonates and unactivated aromatic amine nucleophiles as substrates. The catalytic process features minimal waste production, ample scope in reaction partners, high asymmetric induction up to 97% ee, and operational simplicity.
1 September 2016 in Journal of the American Chemical Society
Significant progress has been observed in recent years in the synthesis of allylic amines, which are important building blocks in synthetic chemistry. Most of these processes are effective toward the preparation of allylic amines, with limited potential to introduce three or four different substituents on the olefinic unit in a stereocontrolled fashion. Therefore, the discovery of a mild and operationally simple protocol allowing such challenging stereoselective synthesis of multisubstituted allylic amines remains an inspiring target. Herein, we report the first general and practical methodology for the stereoselective synthesis of tri- and tetrasubstituted allylic amines based on Pd-catalyzed conversion of allyl surrogates readily obtained from cyclic vinyl carbonates. These rare conversions are characterized by excellent stereoselectivity, operational simplicity, mild reaction conditions, and wide scope in reaction partners. DFT studies were performed to rationalize the stereocontrol in these allylic amine formation reactions, and evidence is provided that the formation of a six-membered palladacyclic intermediate leads toward the formation of (Z)-configured allylic amine products.
12 August 2015 in Angewandte Chemie International Edition
An efficient protocol was developed to construct functionally dense quaternary carbons with concomitant formation of a new Csp3-Csp3 bond via Pd-catalyzed decarboxylative transformation of vinyl cyclic carbonates. This redox neutral catalytic system features stereocontrolled formation of multi-substituted allylic scaffolds with an aldehyde functionality generated in situ, and it typically can be performed at room temperature without any additives. DFT calculations provide a rationale towards the selective formation of these compounds, and revealed a complex mechanism that is able to reproduce with the help of microkinetic models the non-trivial dependence between the identity of the product and the nature of the substituents in the substrate.