Andersen chemistry with an α,β-unsaturated sulfinyl chloride: synthesis and Grignard reactions of homochiral cholesteryl (R)S-(E)-t-butylethenesulfinate

The synthesis of thiols, selenols, sulfides, selenides, sulfoxides, selenoxides, sulfones and selenones

“…The reaction of (E)-3,3-dimethylbut-1-enylsulfinyl chloride and (Ϫ)-cholesterol in the presence of quinine or quinidine allows access to either diastereoisomeric sulfinate ester via a combination of kinetic resolution and fractional recrystallisation (Scheme 96). 165 Subsequent reaction with Grignard reagents in an Andersen-type procedure gives the expected enantiomerically enriched vinyl sulfoxides. The procedure is, however, far from general, as only a single α,β-unsaturated sulfinyl chloride has been used.…”

“…The procedure is, however, far from general, as only a single α,β-unsaturated sulfinyl chloride has been used. 165 The allylation of aldehydes under aqueous Barbier conditions using an enantiomerically pure 2-sulfinylallyl chloride gives β-hydroxy vinyl sulfoxides with moderate diastereoselectivity (Scheme 97). 166 Enantiomerically pure α-vinylsulfinyl ketones have been prepared by a novel route involving the asymmetric sulfoxidation of substituted oxathiines (Scheme 98).…”

Steroids: reactions and partial synthesis (1999)

“…Studies on a number of esters of cholesterol have been reported in connection with their biological activity, 155-161 liquid crystal properties, 162,163 and use in chiral induction. 164 The synthesis and biological activity of some further analogues of the hypocholesterolemic agent 4α(2-propenyl)-5α-cholestan-3α-ol have been reported. 165 The antiproliferative activity of some C-7 aminocholestanes has been examined.…”