Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

Autor: Reji Thomas, Nobuyuki Tamaoki
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Beilstein Journal of Organic Chemistry, Vol 12, Iss 1, Pp 2211-2215 (2016)
Druh dokumentu: article
ISSN: 1860-5397
DOI: 10.3762/bjoc.12.212
Popis: Single crystal X-ray diffraction has been used as one of the common methods for the unambiguous determination of the absolute stereostructure of chiral molecules. However, this method is limited to molecules containing heavy atoms or to molecules with the possibility of functionalization with heavy elements or chiral internal references. Herein, we report the determination of the absolute stereostructure of the enantiomers of molecule (E)-2, which lacks the possibility of functionalization, using a reverse method, i.e., defunctionalization of its precursor of known stereostructure with bromine substitution (S-(−)-(E)-1). A reductive debromination of S-(−)-(E)-1 results in formation of one of the enantiomers of (E)-2. Using a combination of HPLC and CD spectroscopy we could safely assign the stereostructure of one of the enantiomers of (E)-2, the reduced product R-(−)-(E)-1.
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