Silylenes pentadienes

Tang and coworkers have extended the studies of the addition of SiH2 and Sip2 to the pentadienes. For each of these two silylenes, the relative reac-... 

A mixed di-f-butylsilylene has been prepared from (5)-5-hexen-2-ol and prochiral l,4-pentadiene-3-ol for synthesis of (25, 7S)-dibutyroxynonane, the sex pheromone of Sitodiplosis mosellana. The intermediate 43 was then subjected to ring closing metathesis to provide the diene 44 in 70% yield over two steps (eq 16). Deprotection of the nine-membered silylene was achieved using TBAF under refluxing condition in the presence of molecular sieves. Reduction with H2/Pt02 and diacetylation yielded the desired (25, 7S)-dibutyroxynonane in 22% overall yield. ... 

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