Caesalminaxins A–L, Cassane Diterpenoids from the Seeds of Caesalpinia minax

Fourteen new cassane diterpenoids, caesalminaxins A–L (1–14), and three known compounds were isolated from the seeds of Caesalpinia minax. Among the new diterpenoids, compounds 3 and 4 possess a rare spiro C/D ring system. The C-16 epimeric mixture 1/2 has an unprecedented carbon skeleton, presumably derived from 3 by cleavage of the C-13–C-14 bond. Compound 5 is the first example of a cassane diterpenoid with a spiro A/B ring system. The...