摘要:
The reactivity of stabilized-nucleophilic carbene tricyclo[6.2.1.0(2.7)[undec-9-en-11-ylidene (9) toward C-H insertions has been investigated. It is shown that 9 can only insert into acidic C-H bonds, for example, in malononitrile. In this case, evidence for a stepwise process has been obtained. Protonation of the carbene leads to an ion pair composed of a carbocation and a carbanion, which subsequently reacts and gives rise to the formal insertion product anti 10. (C) 2008 Elsevier Ltd. All rights reserved.