A new synthesis of spiropyrrolidine–tetralones via an unexpected formal ring-contraction of 4-disubstituted piperidine to 3-disubstituted pyrrolidine
作者:Upul K. Bandarage、Robert J. Davies
DOI:10.1016/j.tetlet.2010.09.142
日期:2010.12
We have developed an efficient synthesis of novel racemic spiropyrrolidine–tetralones via an unexpected ring-contraction reaction of a 4-disubstituted piperidine to 3-disubstituted pyrrolidine. We suggest that intramolecular quaternization of the piperidine nitrogen of compound 7 occurs to form a bridged bicyclic quaternary ammoniumsalt intermediate 10. The ring opening of 10 with cyanide resulted