Regiodivergent Conversion of Alkenes to Branched or Linear Alkylpyridines

Abstract

Herein we report a practical protocol for the visible-lightinduced regiodivergent radical hydropyridylation of unactivated alkenes using pyridinium salts. This approach provides a unified synthetic platform to control the regioselectivity of the synthesis of linear or branched C4-alkylated pyridines. A remarkable selectivity switch from the antiMarkovnikov to the Markovnikov product can be achieved by the addition of tetrabutylammonium bromide. The versatility of this protocol is further demonstrated based on the late-stage functionalization in pharmaceuticals.