From Olefination to Alkylation: In-Situ Halogenation of Julia–Kocienski Intermediates Leading to Formal Nucleophilic Iodo- and Bromodifluoromethylation of Carbonyl Compounds
作者:Yanchuan Zhao、Bing Gao、Jinbo Hu
DOI:10.1021/ja301601b
日期:2012.4.4
acceptors. However, direct introduction of -CF(2)I and -CF(2)Br groups through nucleophilic addition is particularly challenging because of the high tendency of decomposition of CF(2)Br(-) and CF(2)I(-) to difluorocarbene. In this work, we have developed a formal nucleophilic iodo- and bromodifluoromethylation for carbonyl compounds. The key strategy of the method is the halogenation of in situ-generated
碘和溴二氟甲基化化合物是重要的合成中间体和卤素键受体。然而,通过亲核加成直接引入 -CF(2)I 和 -CF(2)Br 基团特别具有挑战性,因为 CF(2)Br(-) 和 CF(2)I(-) 的分解趋势很高到二氟卡宾。在这项工作中,我们开发了羰基化合物的正式亲核碘和溴二氟甲基化。该方法的关键策略是将 Julia-Kocienski 反应中原位生成的亚磺酸盐中间体卤化,将反应途径从传统的烯化转变为烷基化。在产物的晶体结构中观察到卤烃和芳族供体之间有趣的卤素-π 相互作用。