Cyclization of Trichloroacetimidates by Olefin Aminopalladation β-Heteroatom Elimination
作者:Ansis Maleckis、Ieva Jaunzeme、Aigars Jirgensons
DOI:10.1002/ejoc.200900917
日期:2009.12
The cyclization of δ-acetoxy-O-allyl- and ϵ-acetoxy-O-homoallyl-trichloroacetimidates to 4-vinyloxazolines and a 4-vinyldihydrooxazine has been efficiently achieved by olefin aminopalladation–β-heteroatom elimination. (Z)-Allylic imidates bearing a secondary δ-acetoxy group underwent PdII-catalysed cyclization to give the E isomers of 4-vinyloxazolines selectively and gave no Overman rearrangement
δ-乙酰氧基-O-烯丙基-和ε-乙酰氧基-O-高烯丙基-三氯乙酰亚胺酯环化为4-乙烯基恶唑啉和4-乙烯基二氢恶嗪已通过烯烃氨基钯化-β-杂原子消除有效实现。带有仲 δ-乙酰氧基的 (Z)-烯丙基亚胺酸酯经过 PdII 催化环化,选择性地产生 4-乙烯基恶唑啉的 E 异构体,并且没有产生 Overman 重排产物。使用手性底物,已经证明环化成 4-乙烯基恶唑啉的发生具有高手性转移。立体选择性 E 异构体的形成和手性转移为讨论可能的反应机理提供了基础。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)