Tricarabrol A-C, three sesquiterpene lactone trimers were identified from Carpesium farberi. Tricarabrol A and B are a pair of stereoisomers possessing a novel C44 skeleton featuring no extra ring system beyond the sesquiterpene scaffolds. A combined computational and experimental study on absolute configurations is reported. The biosynthetic pathways including Alder-ene reaction, [3 + 2] cycloaddition, and Michael addition reaction are proposed. Due to the lack of the key ROESY correlations, the configurations of A(C-11’) and C(C-6’ and C-11’’) cannot be experimentally determined. Based on the experimental and DFT-computed 13C and 1H NMR chemical shifts, the configurations are predicted to be A(11’R*) and C(6’R* 11’’R*) by the DP4+ analysis. Additionally, preliminary results on sesquiterpene lactone tetramers and accelerated computational screening of conformers using neural network potential are given.

Tricarabrols A-C, three sesquiterpene lactone trimers featuring methylene-tethered linkage from Carpesium farberi

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.