Ma Xiaoshen, Herzon Seth B
Department of Chemistry , Yale University , New Haven , Connecticut 06520 , USA . Email:
Chem Sci. 2015 Nov 1;6(11):6250-6255. doi: 10.1039/c5sc02476e. Epub 2015 Aug 21.
Classical methods for alkene hydrogenation typically reduce less-substituted or more-strained alkenes, or those in proximity to a directing group, most rapidly. Here we describe a cobalt-mediated hydrogenation protocol that provides complementary selectivities in the reduction of several classes of olefins and alkynes. The selectivity of this reduction derives from a hydrogen atom transfer mechanism, which favors the generation of the more stable alkylradical intermediate. We also report the first alkene hydrobromination, hydroiodination, and hydroselenylation by a hydrogen atom transfer process.
传统的烯烃氢化方法通常最快速地还原取代较少或张力较大的烯烃，或者那些靠近导向基团的烯烃。在此，我们描述了一种钴介导的氢化方法，该方法在几类烯烃和炔烃的还原中提供了互补的选择性。这种还原反应的选择性源于氢原子转移机制，该机制有利于生成更稳定的烷基自由基中间体。我们还报道了首例通过氢原子转移过程进行的烯烃氢溴化、氢碘化和氢硒化反应。
