Determination of the Absolute Configuration of Two Pairs of C-8-C-9 ' Linked Neolignan Enantiomers

Two pairs of new neolignan enantiomers, (+/-)-torreyayunan A (1a/1b) and (+/-)-torreyayunan B (2a/2b), featuring a rare C-8-C-9 linked skeleton, were isolated from leaves and twigs of Torreya yunnanensis. Their absolute configuration involving two chiral centers was determined by combined spectral and Density Functional Theory (DFT) calculation. This is the first report of the absolute configuration of this group of neolignans. Chirality 26:825-828, 2014. (c) 2014 Wiley Periodicals, Inc.