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[摘要]:Julia-Kocienski olefination has been successfully employed to convert carbonyl compds. into the corresponding Boc-protected 1,3-pentadienyl amines in a C4N homologation process. Good to excellent yields are achieved in THF using MHMDS as base to deprotonate the precursor 1-phenyl-1H-tetrazol-5-ylsulfone reagent. The nature of the metallic counteraction dramatically affects the stereoselectivity of the newly formed alkene: good levels of 2E,4E-stereoselectivity are achieved using KHMDS whereas LiHMDS gives a predominance of the 2E,4Z-dienyl product. |
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