Dichlorocarbene Addition to [5]Metacyclophane; Experimental and Calculational Evidence for a [1,5] Sigmatropic Chlorine Shift in a Bridged Cycloheptatriene
作者:Maurice J. van Eis、Barbara S. E. van der Linde、Franciscus J. J. de Kanter、Willem H. de Wolf、Friedrich Bickelhaupt
DOI:10.1021/jo000197d
日期:2000.7.1
In contrast to the terminal phosphinidene complex PhPW(CO)(5) (2), which adds to [5]metacyclophane (1) in a 1,4-fashion, dichlorocarbene preferentially adds in a 1,2-fashion to the formal "anti-Bredt" type double bond of the aromatic ring of 1 to afford the norcaradiene 11b, which immediately rearranges to the bridged cycloheptatriene 12b and further by a [1,5] sigmatropic chlorine migration to the
与末端膦亚膦配合物PhPW(CO)(5)(2)以1,4-形式添加到[5]甲基环已烷(1)相比,二氯卡宾优先将1,2-形式添加到正式的“ 1的芳环的“ Bredt”型双键得到正二十碳烯11b,其立即重排至桥连的环庚三烯12b,并通过[1,5]σ氯迁移至异构体13b作为第一个可观察到的产物。较慢地,后者通过解离机理异构化得到15b。一项计算研究支持以下观点,即[1,5]氯在重排12b-> 13b中的迁移基本上与较小的电荷分离相一致,为此计算出70.2 kJ mol(-)(1)的激活势垒。相反,在平面模型化合物7中类似的[1,5]氯迁移