Carbenoid

In chemistry, a carbenoid a reactive intermediate, which has the characteristic property as a carbene, or is used as a source of carbene. They are produced in situ from geminal dihalo compounds by transmetalation eg with organolithium compounds or by metalation by reaction with the elemantaren metals.

Carbenoid occur in a series of reactions as a reactive intermediate. This includes, for example, the Simmons-Smith reaction. In this case, the carbenoid is obtained by reaction of diiodomethane with a zinc - copper couple. This is then reacted with an alkene to a cyclopropane; actually a typical reaction of a carbene.

Another example of a reaction of carbenoids is the Fritsch - Butt -Wiechell rearrangement. By lithiation with butyllithium a geminal Vinyldihalogenids the carbenoid is obtained. This then rearranges to the substituted acetylene ( alkyne ).