In:
European Journal of Organic Chemistry, Wiley, Vol. 2008, No. 19 ( 2008-07), p. 3382-3388
Abstract:
The enantiopure bridged bis‐dioxine 4 , a dissymmetric dicarboxylic acid exhibiting axial chirality, can easily be synthesized and serve as host for separating and/or transporting chiral guest molecules. Racemic 4 gives with ( R )‐ and ( S )‐1‐phenylethylamine the corresponding pure diastereomeric salts 7 and 8 . The absolut configuration of the diacid 4 in the diastereomeric salt 7 containing ( R )‐1‐phenylethylamine was confirmed to be R by X‐ray crystal structure analysis, which also confirmed its concave nature. Release of the acid‐sensitive pure enantiomers ( R )‐ 4 as well as ( S )‐ 4 was achieved conveniently by use of dry flash‐chromatography on silica. The CD spectrum shows a positive Cotton effect of the ( S )‐enantiomer at 206 nm. The enantiomeric purity was proved by 1 H NMR discrimination of the diastereomeric salts with ( R , R )‐1,2‐bis(4‐methoxyphenyl)ethane‐1,2‐diamine as the base. The dicarboxylic acid ( R )‐ 4 can be used as chiral auxiliary as demonstrated by the difficult resolution of racemic N , N ′‐di‐ tert ‐butyl‐1,2‐bis(4‐methoxyphenyl)ethane‐1,2‐diamine 9 .(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Type of Medium:
Online Resource
ISSN:
1434-193X
,
1099-0690
DOI:
10.1002/ejoc.v2008:19
DOI:
10.1002/ejoc.200800109
Language:
English
Publisher:
Wiley
Publication Date:
2008
detail.hit.zdb_id:
1410000-9
detail.hit.zdb_id:
1475010-7
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