Copper-catalyzed cascade reactions of α,β-unsaturated esters with keto esters

Abstract

SummaryA copper-catalyzed cascade reaction of α,β-unsaturated esters with keto esters is reported. It features a copper-catalyzed reductive aldolization followed by a lactonization. This method provides a facile approach to prepare γ-carboxymethyl-γ-lactones and δ-carboxymethyl-δ-lactones under mild reaction conditions.

Diastereoselective Synthesis of γ-Lactams and δ-Lactams via a Conjugate Addition-Initiated Tandem Reaction

“…The scope of ,-unsaturated ester was extended to dimethyl 2-methyleneglutarate (4), and the -lactam was envisioned. As for the cases of ketones as enolate acceptors, 18 -lactam 5a was indeed obtained in either THF or toluene, albeit in low yields (Table 4, entries 1 and 2). The major isomer was assigned as the (4S*,5S*), in which the exo-ester and C-linked Ph arrayed on the same surface of the ring.…”