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Gold‐Catalyzed Oxidation of Internal Alkynes into Benzils and its Application for One‐Pot Synthesis of Five‐, Six‐, and Seven‐Membered Azaheterocycles
Author(s) -
Dubovtsev Alexey Yu.,
Dar'in Dmitry V.,
Krasavin Mikhail,
Kukushkin Vadim Yu.
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201900108
Subject(s) - chemistry , benzil , alkyne , reagent , combinatorial chemistry , catalysis , chlorobenzene , ring (chemistry) , organic chemistry , medicinal chemistry
Internal alkynes have been shown to undergo oxidation to substituted benzils (1,2‐diarylethane‐1,2‐diones) by α ‐picoline N ‐oxide in the presence of Ph 3 PAuNТf 2 (5 mol‐%). In addition to the unsubstituted benzil, the method allows preparing, under markedly mild conditions (50 °C in chlorobenzene), various non‐symmetrical products, including heteroaromatic versions thereof which are much more difficult to obtain otherwise. This gold(I)‐catalyzed transformation was integrated into one‐pot reaction sequence delivering a range of 5‐ to 7‐membered ring systems (imidazoles, quinoxalines, 1,2,4‐triazines, pyrazines, and 1,4‐diazepines), thus linking these important heterocyclic motifs to the internal alkyne reagent space.