Cresswell Alexander J, Eey Stanley T-C, Denmark Scott E
EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ (UK).
Organic Chemistry, Institute of Chemical and Engineering Sciences, A*STAR, Singapore 138667 (Singapore).
Angew Chem Int Ed Engl. 2015 Dec 21;54(52):15642-82. doi: 10.1002/anie.201507152. Epub 2015 Dec 2.
Although recent years have witnessed significant advances in the development of catalytic, enantioselective halofunctionalizations of alkenes, the related dihalogenation of olefins to afford enantioenriched vicinal dihalide products remains comparatively underdeveloped. However, the growing number of complex natural products bearing halogen atoms at stereogenic centers has underscored this critical gap in the synthetic chemist's arsenal. This Review highlights the selectivity challenges inherent in the design of enantioselective dihalogenation processes, and formulates a mechanism-based classification of alkene dihalogenations, including those that may circumvent the "classical" haliranium (or alkene-dihalogen π-complex) intermediates. A variety of metal and main group halide reagents that have been used for the dichlorination or dibromination of alkenes are discussed, and the proposed mechanisms of these transformations are critically evaluated.
尽管近年来烯烃的催化对映选择性卤官能化发展取得了重大进展，但烯烃的相关二卤化反应以提供对映体富集的邻二卤化物产物仍相对欠发达。然而，越来越多在立体中心带有卤素原子的复杂天然产物凸显了合成化学家工具库中的这一关键差距。本综述强调了对映选择性二卤化过程设计中固有的选择性挑战，并制定了基于机理的烯烃二卤化分类，包括那些可能规避“经典”卤鎓（或烯烃 - 二卤化物π - 络合物）中间体的反应。讨论了用于烯烃二氯化或二溴化的各种金属和主族卤化物试剂，并对这些转化反应提出的机理进行了严格评估。
