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A new approach in exciton‐coupled circular dichroism (ECCD)—insertion of an auxiliary stereogenic center
Author(s) -
Person Richard V.,
Monde Kenji,
Humpf Hansulrich,
Berova Nina,
Nakanishi Koji
Publication year - 1995
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.530070304
Subject(s) - stereocenter , chromophore , chemistry , exciton , circular dichroism , cyclohexane , center (category theory) , stereochemistry , chirality (physics) , crystallography , photochemistry , enantioselective synthesis , organic chemistry , catalysis , physics , condensed matter physics , nambu–jona lasinio model , chiral symmetry breaking , quantum mechanics , quark
There are cases in which exciton coupling between two chromophores does not occur because the two electric transition moments which should interact are coplanar. This is seen with cyclohexane‐1,4‐diols (both ee or ea) and a wide variety of 3‐hydroxy carotenoids, 3‐hydroxyretinoids, etc. A general approach to deal with such cases is to acylate one of the hydroxyl groups with a chiral allenic acid substituted with a suitable chromophore, e.g., CHROMCH C CH‐COOH. The allenic bond introduces a 90° twist at the italicized central carbon so that the allenic CHROM now couples with the second chromophore. This concept of introducing an auxiliary allenic center should be of general applicability in other similar cases. © 1995 Wiley‐Liss, Inc.