Deprotonation of [Mo(COMe)(CO)2(PPh2H)(η-C5H5)] and reaction with activated alkynes: controllable formation of vinylphosphine and η3-acryloyl ligands
Abstract
Deprotonation of the CCO2Me) afforded the vinylphosphine complex trans-[Mo(COMe)(CO)2{PPh2C(CO2Me)
CHCO2Me}(η-C5H5)] 2a after protonation. The crystal structure of this compound confirms that the
CHCO2Me)(η-C5H5)] 2b with complete regioselectivity but less stereoselectivity in that three isomers (trans-E, trans-Z and cis-E) are formed in a ratio of 9.4∶2.8∶1. Deprotonation of 1 at room temperature, which has previously been shown to form the anion [Mo(CO)2(PPh2COMe)Cp]− by migration of the
CHCO2Me}(CO)(PPh2COMe)(η-C5H5)] 3a, accompanied by the chelating vinyl species [Mo{C(CO2Me)
CHCOOMe}(CO)2(η-C5H5)] 4. A similar reaction with
CHCO2Me)(CO)(PPh2COMe)(η-C5H5)] 3b but in this case the isomeric
CHCO2Me)(CO)2(PPh2COMe)(η-C5H5)] 5 was formed as the minor product. Finally, deprotonation of 1 at room temperature followed by treatment with DMAD without subsequent addition of acid gives the metallacycle [Mo{PPh2COCH
C(CO2Me)}(CO)2(η-C5H5)] 6.