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1,2,4‐Cyclohexatriene, an Isobenzene, and Bicyclo[4.4.0]deca‐1,3,5,7,8‐pentaene, an Isonaphthalene: Generation and Trapping Reactions
Author(s) -
Christl Manfred,
Braun Martin,
Müller Germar
Publication year - 1992
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199204731
Subject(s) - methyllithium , cycloaddition , geminal , chemistry , cyclopentadiene , styrene , bicyclic molecule , photochemistry , medicinal chemistry , epoxide , computational chemistry , organic chemistry , catalysis , polymer , copolymer
The addition of bromofluorocarbene to cyclopentadiene and indene yields stable geminal endo ‐fluoro, exo ‐bromocyclopropane derivatives, which when treated with methyllithium lead to isobenzene 1 and isonaphthalene 2 , respectively. These cycloallenes can be trapped in cycloaddition reactions, for example with styrene. This reaction sequence can be converted into a one‐pot procedure if dibromocarbene is generated at low temperatures from tetrabromomethane and methyllithium and treated in situ for the subsequent reactions.— Because the synthesis of a new isomer of benzene is not reported every day, the experimental study immediately precedes this profile of isobenzene 1 obtained from quantum chemical calculations. These results include data regarding its heart of formation, equilibrium geometry, racemization, diradical character, IR spectrum, and chemoselectivity in its [2 + 2] cycloaddition reaction with styrene.