Unusually Coordinated Phosphorus Compounds; 36. Phosphavinyldiazoalkane/1,2,4-Diazaphosphole Cyclization

Article abstract of DOI:10.1055/s-1989-27302

In the reactions of bis(trimethylsilyl)methylenechlorophosphine (7) and chloro(phenyltrimethylsilylmethylene)phosphine (16) with metalated diazomethane derivatives (N2=C(M)R), the primarily formed substituted phosphavinyldiazoalkanes (13a, b and 17) can only, if at all, be isolated and characterized spectroscopically at -78 deg C.At the latest during thawing, they undergo <1,5> cyclization reactions to furnish the 1H-1,2,4-diazaphospholes 15 or 18.The silyl groups bonded to the nitrogen atoms in the latter compounds can be readilycleaved hydrolytically to give the corresponding N-unsubstituted 1H-1,2,4-diazaphospholes 11 and 19. (Diazotrimethylsilylmethyl)(phenyltrimethylsilylmethylene)phosphine (17) takes part in a 1,3-dipolar cycloaddition reaction with (2,2-dimethylpropylidyne)phosphine (20) to produce 3-tert-butyl-1-trimethylsilyl-5-(phenyltrimethylsilylmethylene)phosphino-1H-1,2,4-diazaphosphole (23).