Evidence for the cyclic CN2 carbene in solution.
Diazirinylidene (c-CN2) is formally the simplest of the N-heterocyclic carbenes. The intermediacy of this elusive species in the fragmentation of butyl 3-bromodiazirine-3-carboxylate (1a) with pent-4-en-1-ols and their sodium alkoxides in DMF is supported by the formation of 2-oxabicyclo[4.1.0]heptanes and dipentenoxymethanes. These products result from an intramolecular [2 + 1] cycloaddition and O-H insertion, respectively, of pentenoxymethylenes suggested to originate from the reaction of the electrophilic c-CN2 with an alkoxide ion. The reaction of 1a with primary or secondary amines in methanol affords the corresponding 3-bromodiazirine-3-carboxamides.
Department of Organic Chemistry, Institute of Chemical Technology , Technická 5, 166 28 Prague, Czech Republic.
Eva
E
Hanzlová
Rafael
R
Navrátil
Jan
J
Čejka
Stanislav
S
Böhm
Tomáš
T
Martinů