Facile Preparation of Alkylidenesuccinimides from Maleimides via the Phosphoniosilylation Process

Abstract

β-Functionalization of α ,β-unsaturated carbonyl compounds can be effected by a variety of methods, which generally involve either the organometallic conjugate addition procedures followed by enolate trapping and subsequent oxidation 1 or the dipole reversal process involving the conversion of α ,β-unsaturated carbonyl compounds into βacylvinyl anion equivalents. However, the former procedures are sometimes inadequate and the requisite organocuprates are difficult to obtain. 2 In the case of enones, very efficient and practical β-functionalization methods utilizing the phosphoniosilylation process, one of the latter processes, have been previously developed by Kozikowski, Kim and Lee. 3-5 Recently, we have reported that such procedure can also be employed to α ,β-unsaturated lactones and esters by effecting β-alkylation, β-hydroxyalkylation, β-conjugate addition of them, and β-sulfenylation (Scheme 1). 6 As an extension of these studies we became interested in investigating the possibility of phosphoniosilylation-based βfunctionalizations of α ,β-unsaturated imides, maleimdes. Herein, we now wish to report facile preparation of alylidenesuccinimides from maleimides via the phosphoniosilylation process.