Synthetic studies on daphniglaucins
The synthetic approach to the core framework of daphniglaucin-type Daphniphyllum alkaloids is described herein. The B–C ring was constructed via a Rh-catalyzed [3+2] cycloaddition. Continuous quaternary centers were installed through [3+2] cycloaddition and alkylation. The attempt to build the A–D ring motif using dipolar cycloaddition of azomethine ylides was extensively investigated.