Metal-free direct alkylation of unfunctionalized allylic/benzylic sp³ C-H bonds via photoredox induced radical cation deprotonation.

ABSTRACT: Despite notable recent efforts, a catalytic and convenient strategy for the direct alkylation of unactivated allylic or benzylic sp³ C-H bonds remains a formidable challenge facing the synthesis community. We herein report an unprecedented allylic/benzylic alkylation using only an organo-photoredox catalyst, which enables coupling of a broad scope of alkenes/arenes and electron-deficient alkenes in an atom- and redox-economic manner. A photoredox induced alkene/arene radical cation deprotonation is proposed to smoothly generate the key allylic and benzylic radical intermediates. It represents the first C-C bond formation via radical cation deprotonation under visible light conditions. The resulting products can be easily scaled up and directly converted to ?,?-unsaturated or ?,?-diaryl-acids, -esters, -amides, -pyrazoles, -isoxazoles, as well as lactones, which enables this mild and selective sp³ C-H alkylation to rapidly access complex bioactive molecules.

SUBMITTER: Zhou R 

PROVIDER: S-EPMC5618257 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature