Reactions of transition-metal carbonyls with organolithium compounds. III. Synthesis of tetracarbonyl (tertiary phosphite) oxy- and amino-carbene complexes of the group VIB metals
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abstract
Compounds of the general composition M(CO)4(P(OCH2)3CC2H5)C(OC2H5)R have been synthesized by the reaction of organolithium reagents with M(CO)5P(OCH2)3CC2H5 under mild conditions, where M = Cr, Mo, W; and R = CH3, C6H5. Aminolysis of these compounds at -70C with ammonia and cyclohexylamine have led to the preparation of M(CO)4(P(OCH2)3CC2H5)C(NHR)R species, where M = Cr, Mo, W; R = CH3, C6H5; and R = H, C6H11. Infrared and proton nuclear magnetic resonance studies have been carried out on these compounds. These carbene complexes have exclusively cis structures with respect to the metal, with the lone exception Cr(CO)4(P(OCH2)3CC2H5)C(OC2H5)C6H5, which exists in both cis and trans isomeric forms. The significance of these stereochemical observations is discussed in terms of the steric and electronic effects involved in the nucleophilic addition reactions of the organolithium reagents with bound carbon monoxide ligands. 1973.
