Transition metal-stabilised vinylketenes
Vinylketene)tricarbonyliron complexes are synthesised from readily-available (vinylketone)tricarbonyliron complexes. They react with isonitriles to give (vinyl- ketenimine)tricarbonyliron complexes and with nucleophiles at C- 1 to give p,y- unsaturated carbonyl derivatives. In contrast (vinylketenimine)tricarbnyliron complexes react with nucleophiles at C-2 to give P,y-unsaturated carbonyl derivatives containing an a quaternary centre. This approach has been used to generate homochiral quaternary centres.