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Homocyclobutadienes and Cyclopropenes by Reaction of a Stable Cyclobutadiene with Diazo Compounds
Author(s) -
Vogelbacher UweJosef,
Eisenbarth Philipp,
Regitz Manfred
Publication year - 1984
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.198407081
Subject(s) - cyclobutadiene , diazomethane , chemistry , diazo , yield (engineering) , medicinal chemistry , ring (chemistry) , stereochemistry , photochemistry , organic chemistry , molecule , materials science , metallurgy
The substituents in the diazoalkane 2 are decisive in determining whether compounds of type 3 or 4 are formed in the reaction with the stable cyclobutadiene 1 . Reaction of 1 with diazomethane or diazoethane affords dihydropyrazole derivatives, from which N 2 can be cleaved off to yield thermally stable homocyclobutadienes such as 3 . With doubly acylated or arylated 2 , azines 4 containing cyclopropenyl groups are formed. These reaction proceed via addition of 2 and ring contraction.