Total Syntheses of Daphnezomine L-type and Secodaphniphylline-type Daphniphyllum Alkaloids via Late-Stage C–N Bond Activation

Here, we report the first total syntheses of daphnezomine L-type alkaloids daphnezomine L methyl ester and calyciphylline K via late-stage C-N bond activation. The first synthesis of secodaphniphylline-type alkaloid caldaphnidine D was also achieved via a similar strategy. Other key transformations employed in our synthesis were a facile vicinal diol olefination and an efficient radical cyclization cascade. Biological studies indicated two synthetic compounds possess promising neuroprotective activity.