摘要
在有机锆络合物(Cp_2ZrCl_2)存在下,取代烯丙基二甲基铝(A,B)可与一烷基或二烷基取代的炔烃发生加成反应。用盐酸处理加成中间体,生成1,4-戊二烯衍生物(1,2)、反应具有很高的立体选择性,几乎100%为同向加成,不发生烯丙基重排。取代烯丙基氯化锌(C,D)在无过渡金属络合物存在下,与炔烃发生加成反应,反应中,伴随完全的烯丙基重排。根据实验结果,对以上两类金属烯丙化反应的机理进行了讨论。
It was found that substituted allylaluminiumreagents(A, B) add to both terminal and nonterminal alkynes inthe presence of zirconium complex(Cp_2ZrCl_2). Treatment of theinitially formed intermediates with an acid gives Various kindsof pentadiene derivatives(1. 2). The reactions are highly ster-eoselective and proceed exclusively by sny-addition withoutallylic rearrangement. Substituted allylzinc ?reagents?(C, D) add to functionalizedalkynes without the presence of any kinds of transition metalcomplexes. The reactions proceed with clean allylic rearrange-ment. The mechanismic aspects of the two allylmetallation reac-tions are discussed according to the experimental observations.
关键词
炔
金属烯丙化
有机金属反应
Organometallic reaction
Reaction mechanism
Allylic rear rangement
Zirconium compound
Reaction selectivity
