The first enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinonemonoimines was realized using a chiralphosphoricacid as catalyst. Various novel (bridged) isoxazoline fused dihydrobenzofurans bearing two continuous quaternary stereocenters were achieved in moderate to good yields (up to 94%) with moderate to good enantioselectivities (up to 98% ee). The absolute configurations
been developed, enabling benign synthesis of valuable benzofuroindolines under sustainable conditions. Mechanistic studies revealed the dual role of iron porphyrin responsible for both phenol oxidation and Lewis acid activation, which differs from the well-explored chemistry of hemin in carbene and nitrene insertion reactions. A preliminary experiment with cytochrome c showed that the turnover of iron
已开发了用于在水溶液中氧化苯酚-吲哚[3 + 2]偶联的hemin / H 2 O 2催化系统,可在可持续条件下良性合成有价值的苯并呋喃二氢吲哚。机理研究揭示了卟啉铁既负责酚氧化又负责路易斯酸活化的双重作用,这与血红素在卡宾和氮烯插入反应中的化学研究方法不同。细胞色素c的初步实验表明,卟啉铁的转换适合大分子环境,效率很高(约13 300 TON)。
Visible-Light-Driven C–H Imidation of Arenes and Heteroarenes by a Phosphonium Ylide Organophotoredox Catalyst: Application to C–H Functionalization of Alkenes
作者:Yasunori Toda、Toya Kobayashi、Fumiya Hirai、Takamichi Yano、Makoto Oikawa、Kimiya Sukegawa、Masahiro Shimizu、Fuyuki Ito、Hiroyuki Suga
DOI:10.1021/acs.joc.3c00988
日期:2023.7.7
Phosphonium ylide catalysis through an oxidative quenching cycle has been developed for visible-light-driven C–H imidation of arenes and heteroarenes. The present protocol could be applied not only to trihalomethylative lactonization reactions involving trifluoromethyl, trichloromethyl, and tribromomethyl radicals but also to the first example of an organophotoredox-catalyzed imidative lactonization