om6b00469_si_001.pdf (29 MB)
Insertion Reactions of Silacyclopropanes: Evidence for a Radical-Based Mechanism
journal contribution
posted on 2016-09-12, 12:03 authored by Christina
Z. Rotsides, K. A. WoerpelSilacyclopropanes
reacted rapidly and selectively with p-benzoquinones
to provide oxasilacyclopentanes. Ring-expansion
products were observed in the absence of a catalyst, elevated temperatures,
or irradiation. As substitution was increased on the silacyclopropane
ring, improved stereoselectivity was observed. In some cases, the
regiochemistry was controlled depending on the extent of stabilization
of the reactive intermediates involved. A radical clock experiment,
along with stereochemical studies, confirmed that radical intermediates
were involved in the ring-expansion reaction. The scope of this radical
reaction was expanded to include dienones, aryl aldehydes, and electron-deficient
enones in addition to benzoquinones. In the case of aryl aldehydes
and electron-deficient enones, the radical reaction can be used to
generate silylenes from silacyclopropanes.