Umpolung α‑Silylation of Cyclopropyl Acetates via Low-Temperature Catalytic C–C Activation

We
report a redox-neutral, catalytic C–C activation of cyclopropyl
acetates to produce silicon-containing five-membered heterocycles
in a highly regio- and chemoselective fashion. The umpolung α-selective
silylation leading to dioxasilolanes is opposed to contemporary β-selective
C–C functionalization protocols of cyclopropanols. Lewis base
activation of dioxasilolanes as α-silyl carbinol equivalents
undergoes the unconventional [1,2]-Brook rearrangement to form tertiary
alcohols. Notably, mechanistic studies indicate that an electrophilic
metal-π interaction harnessing highly fluorinated Tp(CF3)2Rh­(nbd) catalyst permitted a low-temperature
C–C activation.