Abstract: Cyclization of the organometallic complexes CHjC= C (CH*), M (C5H5)(C0) 3 (n= 3, 4, 5; I, M= Mo; 11, M= W) occurred under mild conditions to give cyclized products M (C5H5)(CO) 2 [C (CH3)= C (0)(CH2),](HI, M= Mo; IV, M= W) derived from intramolecular insertion of the acetylenic function into a metal-acyl bond. Yields of 111 were high (> 70%) for n= 3, moderate (-50%) for n= 4, and lower (< 15%) for n= 5. No other isomers or ...
