The synthesis and isolation of synthetically useful eight-membered-ring cyclic allenes is difficult due to the strain induced by incorporating cumulated double bonds within a medium-sized ring. This problem can be circumvented by using silylene transfer chemistry to incorporate a silicon atom into the ring.1 Silver-catalyzed insertions of silylenes into propargylic carbon�oxygen bonds of epoxides form 1,2-silaoxetanes with complete regioselectivity. Aldehydes add to these silaoxetanes in a concerted fashion to provide eight-membered-ring cyclic allenes as single diastereomers. An X-ray crystal structure confirms the stereochemistry of the cyclic allenes and shows that the allene functional group is bent from linearity (the angle at the central carbon is 164�). These strained cyclic allenes are stable to ambient conditions and can be purified by silica gel chromatography. In addition, the di-tert-butylsilyl group can be removed to provide acyclic allenes with hydroxyl functional groups.1 Rotsides, C.Z.; Hu, C.; Woerpel, K.A. Angew. Chem. Int. Ed. 2013  , 52, 13033�13036.

Diastereoselective synthesis of eight-membered ring allenes from propargylic epoxides and aldehydes by silylene insertion into carbon-oxygen bonds

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.