ALPHA-ADDITION OF AMINES, IMINES AND HYDRAZINES TO ALLENYLIDENE COMPLEXES - FORMATION OF CARBENE, ACETIDINYLIDENE AND NITRILE COMPLEXES

Diarylallenylidene(pentacarbonyl)-chromium and -tungsten complexes, (CO)5M=C=C=CR2 (M = W (1), Cr (2)), react with amines, imines and hydrazines by addition of the nitrogen nucleophile to the C(alpha) allenylidene atom. With NEt3 the adduct formation is reversible. With secondary and primary amines, imines and hydrazines, the initially formed N-ylide complexes react readily further to give carbene, azetidinylidene and nitrile complexes, respectively. For example the reaction of (a) 1 and 2 with HNEt2 or H2NPh gives alkenyl(amino)carbene complexes, (CO)5M=C[C(H)=CR2] NR2 (3-5); (b) of 1 and 2 with HN=CR2 gives alkenyl(alkylideneamino)carbene complexes, (CO)5M=C[C(H)=CR2] [N=CR2'] (6,7); (c) of 1 with ((i)Pr)N=C(Ph)H the azetidinylidene complex 9; (d) of 1 with 1,2-disubstituted hydrazines such as H(Me)NN(R)H (R = Me, Ph) alkenyl(hydrazino)carbene complexes, (CO)5W=C[C(H)=CR2] [N(Me)N(R)H] (11) and (e) of 1 with H2NNR1R2 (R1 = R2 = H, Me; R1 = H, R1 = Ph) alkenyl(amino)carbene complexes (13) and/or acrylnitrile complexes, (CO)5W[N = C-C(H)=CR2](12). The structures of representative examples of 6, 11 and 12 were established by X-ray analyses.