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Determination of the absolute configuration of Anisotome irregular diterpenes: Application of CD and NMR methods
Author(s) -
van Klink John W.,
Baek SeungHwa,
Barlow Anna J.,
Ishii Hideki,
Nakanishi Koji,
Berova Nina,
Perry Nigel B.,
Weavers Rex T.
Publication year - 2004
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20074
Subject(s) - absolute configuration , chemistry , chirality (physics) , diterpene , enantiomer , derivatization , diastereomer , stereochemistry , circular dichroism , reagent , organic chemistry , mass spectrometry , chromatography , chiral symmetry , physics , quantum mechanics , nambu–jona lasinio model , quark
Several Anisotome diterpene derivatives were synthesized in an attempt to obtain a crystalline compound for X‐ray analysis. Although we were unable to obtain a suitable crystal, the absolute configuration of the irregular diterpene skeleton was determined using two other techniques: a circular dichroism (CD) protocol based on a tetraarylporphyrin molecular tweezer that allowed prediction of the absolute stereochemistry on a microscale level, and a method employing differences in NMR shifts from derivatization of the naturally occurring acid 1 with enantiomers of a phenylglycine methyl ester (PGME) chiral anisotropic reagent. The excellent agreement between the CD and NMR methods led to the assignment of a 2 S ‐absolute configuration for anisotomenoic acid 1. Chirality 16:549–558, 2004. © 2004 Wiley‐Liss, Inc.