Trithiazyl trichloride, reactions with alkynes

Thiadiazoles have been prepared111 in a one-pot reaction of trithiazyl trichloride with alkynes (see Scheme 25). 

Thiadiazoles can be prepared by the oxidative cyclisation of 1,2-diamines or aminocarboxamides. Condensation of snlfamide (S02(NH2)2) with 1,2-diketones gives 1,2,5-thiadiazole 1,1-dioxides. A good general method is the reaction of trithiazyl trichloride with activated alkenes and alkynes this method is also useful for the fusion of a 1,2,5-thiadiazole onto other heterocycles, such as pyrroles. The reaction possibly proceeds via cycloaddition to an N-S-N unit in the trithiazine ring. "... 

Reaction of [CpCr(CO)3] Na+ with S3N3CI3 (/.e., trithiazyl trichloride) affords both [CpGr(CO)a(NS)] and [ CpCr(CO)a 2S], whose crystal structures have been determined. Rates of displacement of halide from alkyl halides by [CpMo(CO)3]" are sensitive to steric, leaving-group, and counter-ion effects. Attachment of the Gp ligand in [CpMo(CO)3]H to polystyrene has little effect upon the Bronsted acidity of the complex. The chemistry of bis-alkyne complexes of Mo and W of the types [CpM( -hfb)aCl] and [CpM(CO)( -but-2-yne)2]+[PF6] has been further explored. Reactions of the carbyne complex [CpW(CO)a(CAr)] (Ar=p-tolyl) with chelating bisphosphines afford [Pg.288]

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