From 1,2-dialkoxyalkanes to 1,4-dioxanes. A transformation mediated by NbCl5 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 NbCl5 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-CH3 bond, followed by (ii) cleavage of the second O-CH3 bond and one of the two O-CH2 linkages. The characterization of intermediate complexes and the isolation of NbOCl3(dme) are reported.