An Efficient Derivation of the Versatile Chiron Antipode 1-tert-Butyldimethylsilylpenta-1,4-diyn-3-ol: Application to the Synthesis of (15E,R,R)-Duryne.
The title chiron, 1-tert-butyldimethylsilylpenta-1,4-diyn-3-ol (5), an essential segment of various bioactive polyacetylenic alcohols, has been efficiently resolved via a lipase-catalyzed acylation strategy. Lipases from different Pseudomonas species and Candida rugosa (CRL) furnished its (S)-antipode (as esters) with 86-96% ee. However, the (R)-alcohol 5 could be prepared with acceptable enantiomeric purity (93% ee) only using CRL-vinyl acetate-diisopropyl ether as the reagent protocol and under double filtration conditions. The chiron alcohol was then extended to the target compound (15E,R,R)-duryne (I) by its pyranylation, alkylation with the required achiral C(20)-alpha,omega-dibromide 15, and suitable functionalization.
Sharma
A.
A
Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai-400 085, India.
Chattopadhyay
S.
S