CONJUGATE ADDITION OF ORGANOCUPRATES TO ALPHA, BETA-UNSATURATED DIAZOALKANE COMPLEXES OF MOLYBDENUM AND TUNGSTEN - BETA-MONOALKYLATION AND ALPHA, BETA-DIFUNCTIONALIZATION OF ALPHA, BETA-UNSATURATED DIAZOALKANE LIGANDS

Beta-Alkylation of alpha,beta-unsaturated diazoalkane complexes [MF(NN=CHCR=CHR1)(dpe)2]X (1,M = W, Mo; X = BF4, PF6; dpe = Ph2PCH2CH2PPh2) by lithium dimethyl- or diphenylcuprates LiCuR22 leads to the formation of the alkenyldiazenido complexes [MF(N=NCH=CRCHR1R2)(dpe)2] (2). Protonation of 2 at the alpha-carbon of the alkenyldiazenido ligands produced beta-monoalkylated diazoalkane complexes in moderate to high yields. Complexes 2 also reacted with alkyl halides or isocyanates to give the corresponding alpha-alkylated or acylated diazoalkane complexes, respectively, in good yields, and these reactions provide a method for the alpha,beta-difunctionalization of 1. Hydrolysis of the diazoalkane complexes obtained by the above method in alkaline THF-H2O under air yielded the corresponding aldehydes. Reaction of alpha,beta-acetylenic diazoalkane complexes [WF(NN=CHC=CR1)(dpe)2]X (6) with LiCuR22 followed by protonation or treatment with I2 gave [WF(NN=CHCH=CR1R2)(dpe)2]X or [WF(NN=CHCI=CR1R2)(dpe)2]X, respectively.