Thermal [2+2]-Cycloadditions between the Metallodiphosphene (η5-C5Me5)(CO)Fe-P=P-Mes* and a Phosphaalkyne

Grobe J, Le Van D, Pohlmeyer T, et al. Thermal [2+2]-Cycloadditions between the Metallodiphosphene (η5-C5Me5)(CO)Fe-P=P-Mes* and a Phosphaalkyne. Organometallics. 1998;17(15):3383-3386.The synthesis of trans-1,2-dihydro-1-(2,4,6-tri-tert-butylphenyl)-2-(dicarbonyl-eta(5)-pe ntamethylcyclopentadienylferrio)-4-diisopropylamino-1,2,3-triphosphete (9) was conducted by treating 1-(dicarbonyl-eta(5)-pentamethylcyclopentadienylferrio)-2-(2,4,6-tri-ter t-butylphenyl)diphosphene (7) with an equimolar amount of 2 -diisopropylamino-1-phosphaethyne (2b). Monitoring the reaction by P-31(H-1) NMR evidenced the formation, of trans-1,2-dihydro-1-(dicarbonyl-eta(5)-pentamethylcyclopentadienylferrio )-2-(2, 4, 6-tri-tert-butylphenyl)-4-diisopropylamino-1,2,3-triphosphete (8) as an, intermediate, which in solution slowly isomerized to the final product 9