Azetidinylidene complexes

Historically, vinylidene complexes of zero-valent pentacarbonyl Group 6 metals appeared as a fleeting intermediate for the preparation of Fischer-type carbene complexes. Probably the first example of the formation of such a pentacarbonyl vinylidene complex of a Group 6 metal was proposed in 1974 by Fischer et al, who examined the reaction of pentacarbonyl[hydroxy(methyl)carbene] chromium 1 with dicyclohexylcarbodiimide(DCC) [3]. Thus, treatment of 1 with DCC in CH2CI2 at —20°C rt gave a novel azetidinylidene complex 2 in 47% yield. As a possible... 

Treatment of the tungsten complex [W(=C=C=CPh2)(CO)5[ with benzylidene-isopropylimine gives rise to the formation of the azetidinylidene derivative 41 through a formal [2 + 2] cycloaddition between the Co =Cp moiety and the iminic... 

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