Benzonitrile, reaction with tungsten complexes

An unusual reaction of W111 with nitriles has been reported by Schrock et al. to provide metal a nitrido tungsten complex [46], Treatment of 98 with acetonitrile or benzonitrile provides the tungsten carbyne 99, along with the nitrido complex 100 (Eq. (37)). Additional studies resulted in the identification of reaction conditions that... 

Chromium (and tungsten) imino carbene complexes 113 are found to be synthetic equivalents for nitrile ylides on the basis of the resonance structure (Scheme 5.23) [34]. The reaction of the imino carbene complex 113 with alkyne 114 affords pyrrole 115. Imidazoles 116 and 120, pyrrolidines 118, and oxazoline 119 are also obtained by the [3+2] cycloaddition of the imino carbene complexes 113 with benzonitrile, alkenes 117, and benzaldehyde, respectively. Although the regiochemical outcome of these reactions is unpredictable, the regioselectivity can be correlated with the resonance structure in the case of the reaction with 3-hexyn-2-one. 

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