mexicanolide-type limonoids is described. The acetal/ketal diketoester precursors were prepared from simple starting materials by LiOH-mediated Michael reactions. The ABC tricyclic skeleton bearing multiple stereogenic centers was efficiently constructed by a powerful one-pot cascade reaction, which includes acetal/ketal hydrolysis, double intramolecular aldol condensation, and alkene migration.
Further applications of endocyclic enamine-enone annulations
作者:C.P. Forbes、G.L. Wenteler、A. Wiechers
DOI:10.1016/0040-4020(78)80039-8
日期:1978.1
The totalsynthesis of rac-sceletium alkaloid A41a and of its 3'-demethoxy analogue 1b via the annulation of endocyclic enamines 4a–b is presented. The Michael acceptor 5a is a useful synthon for the two-step synthesis of 2,3-disubstituted pyridines from Δ2-pyrrolines.