alpha-FUNCTIONALIZATION OF TETRAHYDROISOQUINOLINES WITH ACTIVATED ALKYL BROMIDE UNDER PHOTOREDOX CATALYSIS

摘要

Benzylic C-H functionalization of N-aryl-tetrahydroisoquinolines (THIQs) with various benzyl bromides was developed using a photoredox iridium (Ir) catalyst under blue LED irradiation, affording arylmethyl group-substituted THIQs in moderate to good yields (up to 82). This photoredox catalyst-mediated reaction was also applicable to other activated bromides, including allyl bromide, cinnamyl bromide, propargyl bromide, and alpha-bromoacetate. We propose that photoredox catalyst-mediated electron transfer generates a radical species from the THIQ and another radical from the bromide, and then radical-radical cross-coupling occurs to form a new carbon-carbon bond.