Direct Synthesis of Indoles from Azoarenes and Ketones with Bis(neopentylglycolato)diboron Using 4,4′-Bipyridyl as an Organocatalyst
作者:Luis C. Misal Castro、Ibrahim Sultan、Kohei Nishi、Hayato Tsurugi、Kazushi Mashima
DOI:10.1021/acs.joc.0c02661
日期:2021.2.19
2-diarylhydrazines, which rearranged to the corresponding indoles via the Fischer indole mechanism. This organocatalytic system was applied to diverse alkyl cyclic ketones, dialkyl, and alkyl/aryl ketones, including heteroatoms. Methyl alkyl ketones gave the corresponding 2-methyl-3-substituted indoles in a regioselective manner. This protocol allowed us to expand the preparation of indoles having high compatibility
通过在中性反应条件下,在催化量为4,4'-联吡啶的酮和双(新戊基糖基乙酸)二硼(B 2 nep 2)存在下还原偶氮芳烃,制备多官能化的吲哚衍生物。其中,4,4'-联吡啶为有机催化剂来激活B的B-B键2的棉结2和形成ñ,ñ '-diboryl -1,2- diarylhydrazines关键中间体。N,N'-二硼烷基-1,2-二芳基肼与酮的进一步反应得到N-乙烯基-1,2-二芳基肼,它们通过菲歇尔吲哚机理重排成相应的吲哚。该有机催化体系应用于各种烷基环酮,二烷基和烷基/芳基酮,包括杂原子。甲基烷基酮以区域选择性方式得到相应的2-甲基-3-取代的吲哚。该方案使我们能够扩展具有高相容性的吲哚的制备,所述吲哚不仅与给电子和吸电子基团而且与N-和O-保护官能团具有高相容性。