Sarcanolides A and B: two sesquiterpenoid dimers with a nonacyclic scaffold from Sarcandra hainanensis

Two novel lindenane-type sesquiterpenoid dimers, sarcanolides A (1) and B (2), were isolated from the whole plants of Sarcandra hainanensis. These compounds feature a new nonacyclic scaffold in which the bond formation of C-11-C-7' imposed the five-membered lactone ring in a full beta-direction. Their structures, including the absolute configuration, were determined by NMR analysis, CD exciton chirality method, and ECD calculation. (C) 2011 Elsevier Ltd. All rights reserved.