320608-68-2Relevant academic research and scientific papers
Novel pyranylidene complexes from group 6 transition metals and β-ethynyl α,β-unsaturated carbonyl compounds
Ohe, Kouichi,Miki, Koji,Yokoi, Tomomi,Nishino, Fumiaki,Uemura, Sakae
, p. 5525 - 5528 (2000)
The reaction of conjugated enyne-carbonyl compounds such as 1-(alkoxycarbonyl)-2-ethynylcyclo-alkenes and 1-carbamoyl-2-ethylnylcycloalkenes with Mo(CO)5·NEt3 and W(CO)5·THF gave the corresponding 6-alkoxy- and 6-amino-2H-pyranylidene-molybdenum and -tungsten complexes, respectively. The cycloisomerization reaction of the conjugated vinylidene-ene-carbonyl complexes generated from 1-(alkoxycarbonyl)-or 1-carbamoyl-2-ethynylcycloalkenes and metals is a key route to these Fischer-type oxacarbene complexes. The crystal structure of the 6-methoxy-2H-pyranylidene-tungsten complex 2b has been determined by X-ray diffraction. New pyranylidene complexes undergo [4 + 2] cycloaddition reactions with acetylenes to give aromatic rings together with the liberation of metal hexacarbonyls.
