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Benzocyclobutadienes: An Unusual Mode of Access Reveals Unusual Modes of Reactivity
Author(s) -
Xiao Xiao,
Woods Brian P.,
Xiu Wen,
Hoye Thomas R.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201803872
Subject(s) - aryne , alkyne , reactivity (psychology) , chemistry , diene , diels–alder reaction , photochemistry , computational chemistry , medicinal chemistry , organic chemistry , catalysis , medicine , natural rubber , alternative medicine , pathology
The reaction of an aryne with an alkyne to generate a benzocyclobutadiene (BCB) intermediate is rare. We report here examples of this reaction, revealed by Diels–Alder trapping of the BCB by either pendant or external electron‐deficient alkynes. Mechanistic delineation of the reaction course is supported by DFT calculations. A three‐component process joining the benzyne first with an electron‐rich and then with an electron‐poor alkyne was uncovered. Reactions in which the BCB functions in a rarely observed role as a 4π diene component in Diels–Alder reactions are reported. The results also shed new light on aspects of the hexadehydro‐Diels–Alder reaction used to generate the benzynes.