Solvent-free double aza-Michael under ultrasound irradiation: diastereoselective sequential one-pot synthesis of pyrrolidine Lobelia alkaloids analogues
作者:Zacharias Amara、Emmanuelle Drège、Claire Troufflard、Pascal Retailleau、Delphine Joseph
DOI:10.1039/c2ob25963j
日期:——
Novel 2,5-meso-pyrrolidines have been straightforwardly synthesized from readily available symmetrical double Michael acceptors. The key step rested on an aza-Michael addition of primary alkylamines to bis-enones. Competitive Rauhut–Currier and aza-Michael reactions have been highlighted in protic solvent. Ultrasound activation associated with solvent-free conditions led to the expected pyrrolidines in quantitative yields and excellent stereoselectivities. The optimized conditions have been extended to the sonochemical synthesis of pyrrolidine Lobelia alkaloids analogues in short sequences.