Highly diastereoselective titanium tetrachloride-mediated aldol condensation of the bistrimethylsilyl enol ether of acetoacetic ester with 2-benzyloxyhexanal. A synthesis of (–)-pestalotin
Abstract
Titanium tetrachloride-mediated aldol condensation of the bistrimethylsilyl enol ether of methyl acetoacetate (1) with 2-benzyloxyhexanal (3) gives highly selectively (99 : 1) the syn aldol adduct (5); the stereocontrolled synthesis of (–)-pestalotin (9) has been accomplished.