2H-Imidazol-2-ylidene

Cycloaddition with activated alkenes Reaction between 3-substi-tuted imidazole 1-oxides 228 and 2,2-bis(trifluoromethyl)ethene-l,l-di-carbonitrile leads to 2-(l,3-dihydro-2H-imidazol-2-ylidene)malononitriles 304 (2006HCA1304). 

When IPr.Cl is treated with a base (e.g. BuOK, Bu ONa, K2CO3 or CS2CO3), the catbene lrJ-bis(2,6-diisopropylphenyl)-l,3-dihydro-2H-imidazol-2-ylidene [244187-81-3] M 388.6, m 213-217°, is formed and is stable enough to be isolated, stored and is available commercially. The carbene-carbon atom at C2 coordinates with metals and forms C-C bonds, by C-H insertion, with acetylene, MeCN, HCCI3, PhSOCH3, and the stmctures of some of the products have been confirmed by X-ray analysis [Arduengo et al. Helv Chim Acta 82 2348 1999]. 

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