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Gold Catalyzed Photoredox C1‐Alkynylation of N ‐Alkyl‐1,2,3,4‐tetrahydroisoquinolines by 1‐Bromoalkynes with UVA LED Light
Author(s) -
Zhao Yichao,
Jin Jianwen,
Chan Philip Wai Hong
Publication year - 2019
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201801289
Subject(s) - chemistry , regioselectivity , alkyl , photoredox catalysis , alkynylation , derivative (finance) , alkylation , catalysis , halide , medicinal chemistry , stereochemistry , combinatorial chemistry , photochemistry , organic chemistry , photocatalysis , financial economics , economics
A synthetic method that combines [Au 2 (μ‐dppm) 2 ]Cl 2 (dppm=bis(diphenylphosphanyl)methane) and UVA LED (LED=light emitting diode) light (365 nm) to catalyze the regioselective C1‐alkynylation of N ‐alkyl‐1,2,3,4‐tetrahydroisoquinolines (THIQs) with alkynyl bromides is described. The reaction mechanism was delineated to involve a reductive quench pathway to generate the two posited radical species of the nitrogen‐containing heterocycle and organic halide. In contrast, radical formation via an oxidative quench pathway was suggested to be operative in analogous control experiments with a 1‐iodoalkyne. The usefulness of this carbon‐carbon bond forming strategy was also exemplified by its application to the formal synthesis of the opioid analgesic drug methopholine and synthesis of a protoberberine alkaloid derivative.