Wang Han, Toh Ren Wei, Shi Xiangcheng, Wang Tonglin, Cong Xu, Wu Jie
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Republic of Singapore.
College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou, Gansu, China.
Nat Commun. 2020 Sep 8;11(1):4462. doi: 10.1038/s41467-020-18274-2.
Selective deconstructive functionalization of alkenes, other than the well-established olefin metathesis and ozonolysis, to produce densely functionalized molecular scaffolds is highly attractive but challenging. Here we report an efficient photo-mediated deconstructive germinal dihalogenation of carbon-carbon double bonds. A wide range of geminal diiodoalkanes and bromo(iodo)alkanes (>40 examples) are directly prepared from various trisubstituted alkenes, including both cyclic and acyclic olefins. This C=C cleavage is highly chemoselective and produces geminal dihalide ketones in good yields. Mechanistic investigations suggest a formation of alkyl hypoiodites from benzyl alcohols and N-iodoimides, which undergo light-induced homolytic cleavage to generate active oxygen radical species.
除了成熟的烯烃复分解反应和臭氧分解反应外，通过选择性解构官能团化烯烃来制备高度官能团化的分子骨架极具吸引力，但也具有挑战性。在此，我们报道了一种高效的光介导碳 - 碳双键的解构偕二卤化反应。从各种三取代烯烃，包括环状和非环状烯烃，可直接制备多种偕二碘代烷烃和溴（碘）代烷烃（>40例）。这种碳 - 碳双键裂解具有高度的化学选择性，并能以良好的产率生成偕二卤代酮。机理研究表明，由苄醇和N - 碘代酰亚胺形成烷基次碘酸盐，其经光诱导均裂产生活性氧自由基物种。
