From 1,2-dialkoxyalkanes to 1,4-dioxanes. A transformation mediated by NbCl(5)via multiple C-O bond cleavage at room temperature.

The formation of 1,4-dioxanes and alkyl chlorides from the reactions of polyethers (dme, diglyme, 1,2-diethoxyethane, 1,2-dimethoxypropane) with NbCl(5) at room temperature is described; as far as dme is concerned, the reaction mainly occurs in two steps, consisting of (i) cleavage of one O-CH(3) bond, followed by (ii) cleavage of the second O-CH(3) bond and one of the two O-CH(2) linkages. The characterization of intermediate complexes and the isolation of NbOCl(3)(dme) are reported.