Stereoselective alkene synthesis via silicon-directed [2,3]-sigmatropic rearrangements: an approach to leukotrienes

Abstract

A stereoselective [2,3]-sigmatropic (Wittig) rearrangement of prop-2-ynyl 2-silyl allyl ethers 22 leading to E-vinyl silanes, e.g.23 is described. Stereospecific protiodesilylation of 23, via26, next produces the Z-alkene 27. sp-sp and sp-sp² Coupling reactions between the acetylenic alcohol 5 produced from 27, and 3-bromoprop-2-ynol or 3-bromoprop-2-enol THP ether, then leads to the key intermediates 3 and 31 in leukotriene B₄1 synthesis.