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Generation of triplet carbenes by oxidation of an allene compound
Author(s) -
Fukuen Shinichi,
Yamaguchi Torahiko,
Kojima Satoshi,
Yamamoto Yohsuke
Publication year - 2011
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1870
Subject(s) - chemistry , allene , carbene , ketone , dimer , oxidation state , medicinal chemistry , photochemistry , oxide , organic chemistry , catalysis
Computational analysis on the dicationic species generated upon two‐electron oxidation of the corresponding allenic compounds bearing two thioxanthene ( 7a ) or two acridene ( 7b ) moieties indicated that the ground‐state multiplicity would be of the triplet state (Δ E ST = E CS − E T = 12.6 and 14 kcal/mol, respectively). Under this premise, oxidation reactions of 7a and 7b were carried out. In the case of 7b , oxidation with ( p ‐BrC 6 H 4 ) 3 N •+ SbCl 6 − gave a dimer ( 13 ), which could be presumed to have formed by dimerization of the corresponding carbene. Oxidation of 7b in the presence of tetramethylpiperidine N ‐oxide afforded the corresponding ketone derivative ( 14) , thus implying the likelihood of a triplet carbene being the reactive intermediate. These results suggest that double oxidation of heterocyclic allene compounds is viable as a new approach for generating triplet carbenes. Copyright © 2011 John Wiley & Sons, Ltd.