Divergent Total Syntheses of Lycorine Alkaloids via a Sequential C-H Functionalization Strategy.

A Pd-catalyzed one-pot sequential C-H functionalization strategy was utilized to prepare four lycorine alkaloids and one pseudo -lycorine alkaloid from the common intermediate 4 . By switching the followed oxidative conditions of air, DMSO/H 2 O/I 2 , and DMSO/O 2 , based on the Pd(PPh 3 ) 4 /K 2 CO 3 /toluene catalytic system, three key intermediates 12a , 12b , and 12c with different substitution patterns could be obtained in a well-controlled manner. As a result, four natural products γ-lycorane, hippadine, anhydrolycorinone, and anhydrolycorine as well as a pseudo -lycorine alkaloid Δ (4a,10b) -6-oxodihydrolycorine were successfully synthesized within 10 steps through this divergent route.