Subtle effects in the asymmetric epoxidation: dependence of kinetic resolution efficiency on the monodentate alkoxide ligands of the bystander titanium center

One-Pot Asymmetric Synthesis of Acyclic Chiral Epoxy Alcohols via Tandem Vinylation−Epoxidation with Dioxygen

“…Sharpless kinetic resolution − of racemic secondary allylic alcohols with a titanium tartrate catalyst can, in principle, be used to afford the corresponding chiral epoxy alcohol products with good selectivity, regardless of the substitution pattern on the olefin. As with all kinetic resolutions, however, this approach is limited to a maximum yield of 50%.…”

An optimised and recoverable tartrate surrogate for sharpless asymmetric epoxidations

“…The ees of the recovered alcohols 13 shown in Table 4 are followed in parenthesis by the related values obtained using the Sharpless procedure. 15 Overall, these results indicate that the present system is very suited to the kinetic resolution of sterically unencumbered allylic alcohols, with ees of the recovered alcohols only becoming lower in the case of the cyclohexyl-substituted substrate 23, wherein it appears that the presence of a bulky substitu- OH ent adjacent to the hydroxy group lowers the level of differentiation. However, similar increases in bulk at the opposite end of the allylic alcohol function [e.g., 33] appear to have little effect.…”

Stereoselective Reactions of Acyclic Allylic Phosphates with Organocopper Reagents

“…Pyridine was distilled from CaH 2 . The known allylic alcohols 1a , 1b , and 1c 10a were prepared by reacting freshly distilled crotonaldehyde with the corresponding Grignard reagent in diethyl ether under typical reaction conditions; analogously, 1e was prepared by reacting E- 2-heptenal with cyclohexylmagnesium chloride in ether. Benzyltributylstannane was prepared by a method similar to one developed by Seitz and co-workers .…”