Cyaphide-Azide 1,3-Dipolar Cycloaddition Reactions: Scope and Applicability.

Several examples of the cyaphide-azide 1,3-dipolar cycloaddition reaction to afford metallo-triazaphospholes are reported. The gold(I) triazaphospholes Au(IDipp)(CPN R) (IDipp=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; R= Bu, Ad, Dipp), magnesium(II) triazaphospholes, {Mg( NacNac)(CPN R)} ( NacNac=CH{C(CH )N(Dipp)} , Dipp=2,6-diisopropylphenyl; R= Bu, Bn), and germanium(II) triazaphosphole Ge( NacNac)-(CPN Bu) can be prepared straightforwardly, under mild conditions and in good yields, in a manner reminiscent of the classic alkyne-azide click reaction (albeit without a catalyst). This reactivity can be extended to compounds with two azide functional groups such as 1,3-diazidobenzene. It is shown that the resulting metallo-triazaphospholes can be used as precursors to carbon-functionalized species, including protio- and iodo-triazaphospholes.