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Synergistic Steric Effects in the Development of a Palladium‐Catalyzed Alkyne Carbohalogenation: Stereodivergent Synthesis of Vinyl Halides
Author(s) -
Le Christine M.,
Menzies Perry J. C.,
Petrone David A.,
Lautens Mark
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201409248
Subject(s) - steric effects , alkyne , chemistry , isomerization , catalysis , intramolecular force , oxidative addition , reductive elimination , palladium , halide , substrate (aquarium) , aryl , reaction mechanism , combinatorial chemistry , photochemistry , organic chemistry , oceanography , alkyl , geology
We report our finding that by exploiting the synergistic steric effects between substrate and catalyst, an intramolecular Pd‐catalyzed alkyne carbohalogenation can be achieved. This operationally simple method uses the bulky Pd/Q‐Phos combination and allows access to tetrasubstituted vinyl halides from the corresponding aryl chlorides, bromides, and iodides. Steric effects in the substrate play a key role by promoting C sp 2‐halogen reductive elimination and enabling catalytic turnover. Through a reversible oxidative addition mechanism, a thermodynamically driven isomerization reaction is observed at elevated temperatures. Thus by changing the reaction temperature, both stereoisomers of the reaction become readily accessible.