Organische Synthesen mit Übergangsmetallkomplexen, 6: Ketenimin‐Synthese via Ketenimin‐Komplexe, Isocyanid‐Carben‐Addition sowie Ketenimin‐Carben‐Umlagerung in Metallkomplexen

Abstract

Organic Syntheses by Means of Transition Metal Complexes, 6: Synthesis of Ketenimines via Ketenimine Complexes, Isocyanide Carbene Addition and Ketenimine Carbene Rearrangement in Metal Complexes Transition metal carbene complexes of the Fischer type, e. g. pentacarbonyl(methoxymethyl‐carbene)chromium(0), add isocyanides to give ketenimine complexes ( 1 ). Ligand displacement by excess isocyanide affords ketenimines ( 3 ), which can be isolated in good yields. In contrast to free ketenimine, the nucleophilic attack on ketenimine coordinated to a metal occurs at the terminal carbon atom leading to carbene complexes. The structures of the ketenimine complexes of chromium ( 1 ) and tungsten ( 2 ), the product of isomerization ( 5 ) (2) of the chromium complex, and the products formed by addition of methanol or water ( 6 and 7 , resp.) (2) are discussed, using 13 C NMR data.