CpRu]-catalyzed carbene insertions into epoxides: 1,4-dioxene synthesis through S(N)1-like chemistry with retention of configuration.

Abstract

Rather than lead to the usual deoxygenation pathway, metal carbenes derived from α-diazo-β-ketoesters undergo three-atom insertions into epoxides using a combination of 1,10-phenanthroline and [CpRu(CH3CN)3][BAr(F)] as the catalyst. Original 1,4-dioxene motifs are obtained as single regio- and stereoisomers. A perfect syn stereochemistry (retention, e.r. up to 97:3) is observed for the ring opening, which behaves as an S(N)1-like transformation.