Asymmetric Total Synthesis of (+)-Sparteine and the Synthesis of a Readily Accessible (+)-Sparteine Surrogate

摘要

The chiral diamine (-)-sparteine has proven to be a valuable and versatile chiral ligand for asymmetric synthesis. Its utility has been well demonstrated in a variety of reactions such as deprotonations, conjugate additions, and carbometallations. Based on its prior successes, new applications for this ligand continue to be discovered. (-)-Sparteine is a naturally occurring plant alkaloid and is commercially available, while its enantiomer, though also naturally prevalent, is not easily accessible. The utility of sparteine as a chiral ligand has spurred the interest of a number of synthetic groups to come up with total syntheses that would allow access to both antipodes.