Highly stereoselective preparation of enantiomerically pure 1,2-diols: synthesis of (+)-exobrevicomin
作者:Marc Larchevêque、Julien Lalande
DOI:10.1039/c39850000083
日期:——
Reduction of optically pure acyl-lactones (2) by L-Selectride affords monoprotected syn diols with high diastereoselectivity; the reaction was applied to the stereo- and enantio-specific synthesis of (+)-exobrevicomin.
butanolides (R)-(1a) and (R)-(1b), bearing n-alkyl chains, on yeast treatment afford exclusively the syn reduction products (4a) and (4b), whereas the (S) enantiomers yield syn (2a) and (2b) in ca. 6:4 ratio with the anti diastereoisomers (3a) and (3b), respectively. Under the same conditions, (S)-(1c) and (R)-(1c) give rise to syn and anti reduction products in ca. 1:4 and 4:1 ratios, respectively.