A practical access to new pyrrolizine carboxylates via KHMDS-catalyzed carbocyclizations

Abstract

Easy and effective preparation of new 1H-pyrrolizine carboxylates was achieved with high efficiency via KHMDS-induced carbocyclization of N-alkynyl proline carboxylates under substantially mild conditions. Meanwhile, some trans-diiodoallylic N-proline carboxylates were obtained from N-propargyl proline carboxylates using molecular I₂ with or without KHMDS. This method is quite feasible in terms of practical and quick access to the pyrrolizines and their derivatives over the formation of carbanions.

Graphical Abstract

Keywords:

• 5-endo-dig
• A3-coupling
• carbocyclization
• L-proline
• sonogashira coupling

Additional information

Funding

This study was funded by Bolu Abant İzzet Baysal University, Scientific Research Projects Division (BAP grant no. 2015.03.03.931).