Use of Polymer-Supported 4-(N , N -Dimethylamino)pyridine in a Formal Conjugate Addition/Elimination Mediated by an N -Ylide Generated In Situ for the Construction of Highly Functionalized Itaconimides/Alkenes.

A simple, mild, and metal-free cascade reaction has been developed for the construction of highly functionalized olefins. The approach relies on the initial formation of [3+2]-cycloadducts from a pyridinium ylide generated in situ from polymer-bound DMAP (PS-DMAP) with an N -substituted maleimide or an α,β-unsaturated β-keto ester. The cycloadduct decomposes to regenerate supported DMAP and yield a functionalized itaconimide or olefin. The method has a broad substrate scope. The alkene product has been further transformed into trisubstituted furan. PS-DMAP could be reused for five cycles. [ABSTRACT FROM AUTHOR]