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Synthesis, Optical Rotation, and Absolute Configurations of Santinols
Author(s) -
Wu WenJu,
Chen HuiJun,
You Jun,
Wu Yikang,
Liu Bo
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500758
Subject(s) - chemistry , optical rotation , absolute configuration , specific rotation , acylation , stereochemistry , sign (mathematics) , enantiomeric excess , optically active , rotation (mathematics) , enantioselective synthesis , organic chemistry , catalysis , mathematical analysis , geometry , mathematics
Santinols A1 and A2, two of the asymmetric 1,3‐diacylglycerols (1,3‐diacylglycerides) recently isolated from Helichrysum italicum subsp. microphyllum , were synthesized for the first time. The synthetic samples showed essentially the same 1 H and 13 C NMR spectra as reported for natural santinols. The optical rotations were also consistent with those for their natural counterparts, but only for less than an hour after the preparation of the sample solution; the sign of the optical rotation may reverse after a more prolonged time, revealing some so far unknown yet very interesting phenomena that deserve particular attention with regard to assignments of absolute configurations for asymmetric 1,3‐diacylglycerols by comparison of specific rotations. Also of interest is that acylation of the C‐2 OH groups in asymmetric 1,3‐diacylglycerols with 2‐(phenylamino)benzoic acid led to substantially “magnified” specific rotations and thus may help in characterization/identification and rapid estimation of the optical purities of asymmetric 1,3‐diacylglycerols.