Improved synthesis of tert-butanesulfinamide suitable for large-scale production

Computational Rationalization of the Dependence of the Enantioselectivity on the Nature of the Catalyst in the Vanadium-Catalyzed Oxidation of Sulfides by Hydrogen Peroxide

A computational study with the IMOMM(Becke3LYP:MM3) method is carried out on the mechanism of the enantioselective reaction of complex V(O)(L)(OOH), L= bulky tridentate Schiff base, and bis(tert-butyl) disulfide. The reaction with a given L ligand A is first systematically studied: different conformers of the catalyst are optimized, and the large number of associated transition states are systematically searched. The study is then extended to the geometry optimization of selected transition states associated to other ligands B, C, and D, similar to A but differing in the nature of certain substituents R1, R2, R3. The experimental trends in selectivity for catalysts based on ligands A to D are faithfully reproduced by the calculations. Analysis of the computational results leads finally to the formulation of a simple model that can explain one of the most remarkable aspect of this reaction, namely the large effect on enantioselectivity of ligands seemingly far from each other in the catalyst.

The synthesis and directed ortho-lithiation of 4-tert-butylsulfinyl[2.2]paracyclophane

The ortho-lithiation of one diastereoisomer of 4-tert-butylsulfinyl[2.2]paracyclophane is the key step to the synthesis of a range of 4,5-disubstituted [2.2]paracyclophane derivatives.

Synthesis of Enantiopure tert-Butanesulfinamide from tert-Butanesulfinyloxazolidinone

A three-step procedure for the preparation of enantiopure tert-butanesulfinamide 6 in 51% overall yield is described starting from (1R,2S)-N-Cbz-1,2-diphenylaminoethanol. The key step is the reaction of tert-butylmagnesium chloride with N-Cbz-4,5-diphenyl-1,2,3-oxathiazolidine-2-oxide 2 to afford the optical pure tert-butylsulfinyl-4,5-diphenyl-1,3-oxazolidinone 5 via an 1,5-alkoxy anion rearrangement, which is then subject to ammonia hydrolysis with LiNH(2) in liquid ammonia to give (R)-tert-butanesulfinamide 6.

Application ofP,N-Sulfinyl Imine Ligands to Iridium-Catalyzed Asymmetric Hydrogenation of Olefins

The utility of a novel class of P,N-ligands incorporating a chiral sulfinyl imine moiety is demonstrated in the iridium-catalyzed hydrogenation of both functionalized and unfunctionalized olefins, in which enantioselectivities of up to 94% are achieved. The modularity of the P,N-sulfinyl ligand class is highlighted by the facile preparation of a variety of sterically and electronically different ligands. Interesting structure-activity data for both the phosphine and sulfinamide components is provided by this expanded ligand set.