2H-1,2-azaphosphindoles - Synthesis and characterization

The first 1,2-azaphosphindoles 14a,b, 15a,b were obtained in a straightforw ard manner upon heating diphenylzirconocene in the presence of a cyanophosp hane, which afforded azazirconacyclopentenes 11a,b which can be reacted wit h various dichlorophosphanes. The use of the tetrachlorodiphosphane Cl2P(CH 2)(2)PCl2 instead of a dichlorophosphane allowed the preparation of the bis (1,2-azaphosphindoles) 19, 19'. The monosulfur adduct of the azaphosphindol e 14a, i.e. 16a, was characterized by X-ray structure analysis. Alkylation of 14a or 16a with methyltrifluoromethane sulfonate occurred selectively on the intracyclic phosphorus atom or on the sulfur atom, giving the salts 20 or 21, respectively.