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Exploiting Synergistic Catalysis for an Ambient Temperature Photocycloaddition to Pyrazoles
Author(s) -
Lakeland Christopher P.,
Watson David W.,
Harrity Joseph P. A.
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904210
Subject(s) - cycloaddition , photocatalysis , organocatalysis , chemistry , catalysis , pyrazole , sydnone , combinatorial chemistry , nanotechnology , photochemistry , organic chemistry , materials science , enantioselective synthesis , ring (chemistry)
Sydnone‐based cycloaddition reactions are a versatile platform for pyrazole synthesis, however they operate under harsh conditions (high temperature and long reaction times). Herein we report a strategy that addresses this limitation utilizing the synergistic combination of organocatalysis and visible‐light photocatalysis. This new approach proceeds under ambient conditions and with excellent levels of regiocontrol. Mechanistic studies suggest that photoactivation of sydnones, rather than enamines, is key to the successful implementation of this process.