Synthesis and X-ray structure of an unexpected bidentate allene-aminocarbene complex of tungsten

This contribution describes attempts at synthesizing 1,4-bidentate alkyne-ferrocenylaminocarbene complexes of tungsten, chromium and molybdenum. This led to the unexpected formation, upon base-induced propargyl bromide alkylation at nitrogen, of new allene-ferrocenylaminocarbene complexes 5a-c of these metals.