4-Oxo-2,3,5,6-tetrafluorocyclohexa-2,5-dienylidene—A Highly Electrophilic Triplet Carbene
作者:Wolfram Sander、Rolf Hübert、Elfi Kraka、Jürgen Gräfenstein、Dieter Cremer
DOI:10.1002/1521-3765(20001215)6:24<4567::aid-chem4567>3.0.co;2-a
日期:2000.12.15
The 4-oxocyclohexa-2,5-dienylidenes are an interesting class of highly electrophilic carbenes. We investigated the reactivity of the 2,3,5,6-tetrafluorinated and -tetrachlorinated derivatives 1b and 1c with small molecules under conditions of matrix isolation. The reactions with molecular oxygen and with carbon monoxide produce the expected carbonyl O-oxides and ketenes, respectively. As a result of the extreme electrophilicity of 1b and c both carbenes insert with no or very small activation barriers into H2 or the CH bonds of hydrocarbons. Obviously, spin restrictions for these formally spin-forbidden reactions do not result in substantial thermal activation barriers.