By utilizing amino allenes, aldehydes, and aryl iodides as readily available building blocks, a simple and modular synthesis of multisubstituted pyridines with flexible control over the substitution pattern has been achieved. The method employs a two-step procedure involving the preparation of "skipped" allenyl imines and a subsequent palladium-catalyzed cyclization.
Base-Promoted β-C(sp<sup>3</sup>)–H Functionalization of Enaminones: An Approach to Polysubstituted Pyridines
作者:Jinhai Shen、Dingding Cai、Changsheng Kuai、Yunqi Liu、Ming’e Wei、Guolin Cheng、Xiuling Cui
DOI:10.1021/acs.joc.5b00635
日期:2015.7.2
A convenient "one-pot" base-promoted synthesis of polysubstituted pyridines from 1-arylethylamines and ynones through the direct beta-C(sp(3))-H functionalization of enaminones under metal-free conditions has been developed. An intermolecular Michael addition reaction and an intramolecular condensation were involved in this procedure, which features high regioselectivity; high efficiency, and environmental friendliness. Various polysubstituted pyridines were provided in up to 92% yield for 34 examples.