Binap-silver salts as chiral-catalysts for the enantioselective 1,3-dipolar cycloaddition of azomethine ylides and alkenes

Binap-AgSbF6 catalyzed 1,3-dipolar cycloadditions between azomethine ylides and electrophilic alkenes are described and compared with analogous transformations mediated by other Binap-silver(I) salt complexes. Maleimides and 1,2-bis(phenylsulfonyl)ethylene are suitable dipolarophiles for obtaining very good enantioselectivities, even better values are generated by a multicomponent version. There are some very interesting applications of the disulfonylated cycloadducts in the total synthesis of cis-2,5-disubstituted pyrrolidines, precursors of natural products, or valuable intermediates in the synthesis of antiviral compounds.

This work has been supported by the Spanish Ministerio de Ciencia e Innovación (MICINN) through the Hispano-Brazilian project PHB2008-0037-PC and CNPq-2878, Consolider INGENIO 2010 CSD2007-00006, CTQ2010-20387, FEDER, Generalitat Valenciana (PROMETEO/2009/039), and by the University of Alicante. MM-R thanks MEC for a predoctoral fellowship. EC thanks CNPq for a predoctoral Doutorado Sanduíche stay.