2,4-N,N′-Bis(dialkylamido)-2,4-dithioxo-1,3,2λ5,4λ5-dithiadiphosphetanes

Dialkylamide derivatives of the monometadithioxaphosphoric acid stabilised by pyridine as a donor, i.e. [(C5H5N)PS2NR2], readily react with AlCl3. The elimination of the donor and formation of the adduct (C5H5NAlCl3)-Al-. liberates the unstable sigma(3)lambda(5)-phosphoranes (PS2NR2). The latter are stabilised by [2+2] "cycloaddition-dimerization" leading to the title compounds [PS2NR2](2) in nearly quantitative yields. The synthesis and characterisation of two compounds possessing NR2 substituents of very different basicities clearly demonstrate the generalisation of such a procedure as an easy way of accessing further derivatives in this class. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.