Synthesis of Pterocarpan Cabenegrin A-II.

Abstract

Cabenegrin A-II is a molecule found in small quantities in the South American plant commonly called Portuguese Snake Herb, and is useful as a snake and spider anti-venom. Cabenegrin A-II occurs in these plants as a mixture of compounds. It belongs to the biologically active class of compounds known as pterocarpans. Synthetic methods for preparing cabenegrin A-II and other pterocarpans are highly valued. This research develops a novel route to construct the core portion of cabenegrin A-II, which is common to all pterocarpans. This method will allow us to synthesize both ends of the molecule separately. The fragments are then bonded together while the pterocarpan core is synthesized. The strategy used in these experiments will be useful for constructing other biologically important pterocarpans.