Use of 1H NMR chemical shifts to determine the absolute configuration and enantiomeric purity for enantiomers of 3,3′-disubstituted-MeO-BIPHEP derivatives

Autor:	Evgueni Gorobets, Bronwen M. M. Wheatley, Masood Parvez, Brian A. Keay
Rok vydání:	2006
Předmět:	Group (periodic table) Computational chemistry Stereochemistry Chemistry Chemical shift Organic Chemistry Absolute configuration Proton NMR General Chemistry Enantiomer Catalysis
Zdroj:	Canadian Journal of Chemistry. 84:93-98
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v05-230
Popis:	The absolute configuration of a series of 3,3′-disubstituted-MeO-BIPHEP derivatives can be determined by the 1H NMR chemical shift of the methoxyl group when the 3,3′-disubsituted-MeO-BIPHEP derivative is mixed with (–)-(2R,3R)-dibenzoyltartaric acid ((–)-DBTA) (1:2) and its NMR spectrum is run in CDCl3. The chemical shift of the methoxyl group in the Sax enantiomer always occurred at higher field than the corresponding Rax enantiomer. Integration of the corresponding methoxyl signals provides the enantiomeric purity of any mixtures.Key words: assignment of absolute configuration, 2,2′-bis(diphenylphosphino)-1,1′-biaryls, MeO-BIPHEP derivatives, asymmetric Heck reaction, 1H NMR chemical shifts.
Databáze:	OpenAIRE
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