Lewis acid-catalyzed formal [3+2] cycloadditions of N-tosyl aziridines with electron-rich alkenes viaselective carbon–carbon bond cleavageElectronic supplementary information (ESI) available: Complete experimental procedures and characterization data for all new compounds. CCDC 795469(2a) and 795470(3a). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c1cc10926j

A novel, mild, robust catalyst Y(OTf)3for C–C bond heterolysis of N-tosyl aziridines was developed and the resulting metallo-azomethine ylides may readily undergo [3+2] dipolar cycloaddition with an electron-rich olefin viaa stepwise reaction pathway with high regio- and diastereoselectivity leading to substituted pyrrolidines. [ABSTRACT FROM AUTHOR]