Preparation of substituted cyclopentadienes through platinum(II)-catalyzed cyclization of 1,2,4-trienes
Preparation of substituted cyclopentadienes through platinum(II)-catalyzed cyclization of 1,2,4-trienes
复制标题
DOI：
10.1002/anie.200603986
复制
发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Iwasawa, Nobuharu
中科院分区：
文献类型：
--
作者：
Funami, Hideaki;Kusama, Hiroyuki;Iwasawa, Nobuharu
环戊二烯（Cps）是有机和金属有机化学领域中非常有用的合成中间体。它们不仅可用作Diels-Alder反应[1]中的反应性二烯组分，而且可用作制备具有Cp型配体的过渡金属络合物的前体。[2]然而，由于缺乏通用方法[3]以及内环双键的容易迁移，制备定义明确的高度取代的环戊二烯并不一定容易。[4]本文描述了一种基于PtII催化的1，2，4-三烯环化反应制备高度取代的环戊二烯衍生物的新方法，其中铂-卡宾中间体在决定反应途径中起重要作用。我们预期用适当的亲电过渡金属配合物处理1，2，4-三烯[5]会产生α，β-不饱和碳烯络合物III通过π络合物I [6]和/或π阳离子络合物II的环化，并且所产生的碳烯络合物III将进一步经历有用的转化以得到环戊二烯或其衍生物[Eq.①]。
Cyclopentadienes (Cps) are highly useful synthetic intermediates in the field of organic and organometallic chemistry. They are useful not only as a reactive diene component in the Diels–Alder reaction [1] but also as a precursor for the preparation of transition-metal complexes with Cp-type ligands.[2] However, the preparation of well-defined, highly substituted cyclopentadienes is not necessarily easy owing to the absence of general methods [3] and also to the facile migration of the endocyclic double bonds.[4] Herein we describe a novel method for the preparation of highly substituted cyclopentadiene derivatives based on the PtII-catalyzed cyclization of 1, 2, 4-trienes in which platinum–carbene intermediates play an important role in determining the reaction pathways.We expected that treatment of 1, 2, 4-trienes with appropriate electrophilic transition-metal complexes [5] would generate α, β-unsaturated carbene complexes III through cyclization of π complex I [6] and/or pentadienyl cationic complex II, and that the produced carbene complex III would further undergo useful transformations to give cyclopentadienes or their derivatives [Eq.(1)].