Synthesis of stereodefined fused δ-hydroxy-γ-lactones from dealkylative cyclization of epoxy-diesters
摘要:
A dealkylative lactonization of stereodefined aryl-substituted epoxides allows the preparation of densely functionalized fused delta-hydroxy-gamma-lactones having three consecutive stereochemically defined stereocenters. (C) 2011 Elsevier Ltd. All rights reserved.
Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH2 groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalyticcycle involving oxidative