A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10 000 in most cases; S/C = 50 000 or 100 000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26 000 mol mol⁻¹ h⁻¹. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.

We have developed two green, practical, and efficient procedures, including a one-pot one, to synthesize isothiocyanates from amines and carbon disulfide via desulfurization with sodium persulfate. Water is used as the solvent. Basic conditions are necessary for good chemoselectivity for isothiocyanates. Structurally diverse linear and branched alkyl amines and aryl amines are readily converted to isothiocyanates by the two procedures in satisfactory yields. Halogens, benzylic C–H bonds, methylthio, nitro, ester, alkenyl, electron-rich or -deficient (hetero)aryls, acetylenyl, and even phenolic and alcoholic hydroxyls are well tolerated. The one-pot procedure in water can also be used to realize the preparation of chiral isothiocyanates from chiral amines, and the modification of bioactive structures with free amino groups. In large-scale preparation, simple and practical purification procedures independent of column chromatography are developed.

The stereoselectivity of the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents was investigated experimentally by determination of the product stereochemistry and theoretically via DFT calculations. The results indicate that imines preferentially attack the less sterically hindered exo-side of the ketenes to generate zwitterionic intermediates. Subsequently, for cyclic imines, the intermediates undergo a conrotatory ring closure directly to produce β-lactams, while for linear imines, the imine moiety of the intermediates isomerizes to more stable intermediates, which further undergo a conrotatory ring closure to afford trans-β-lactams. The steric hindrance and the isomerization, rather than the torquoelectronic effect, play crucial roles in controlling the stereoselectivity in the practical Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents, although the unaccessible borylketene with a powerful electron acceptor group controls the stereoselectivity torquoelectronically, in theory.

Synthesis of α-heterosubstituted ketones and related heterocyclic structures was achieved through sulfur mediated difunctionalization of internal alkynes in one pot.