Dynamic helical chirality of an intramolecularly hydrogen-bonded bisoxazoline

被引：25

作者：

Preston, AJ ^{[1
]}

Fraenkel, G ^{[1
]}

Chow, A ^{[1
]}

Gallucci, JC ^{[1
]}

Parquette, JR ^{[1
]}

机构：

[1] Ohio State Univ, Dept Chem, Columbus, OH 43210 USA

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2003年 / 68卷 / 01期

关键词：

D O I：

10.1021/jo026496f

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The synthesis and conformational properties of 2,6-bis-[2-((4S)-4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]carbam oylpyridines, 2, have been described. Bisoxazoline 2a was prepared in five steps from 2-nitrobenzoyl chloride in an overall yield of 71%. In contrast to related structures such as 1, bisoxazoline 2a exhibits a highly biased P-type helical conformation in solution and in the solid state. In the crystal lattice, 2a further assembles into a left-handed helical superstructure aligned along the crystallographic c axis. The barrier to helical interconversion, as measured by line-shape analysis of the temperature-dependent H-1 NMR spectra of thiobenzyl derivative 2b, was determined to be quite low (DeltaG(double dagger) = 12.3 kcal/mol), indicating the presence of a highly dynamic helical chirality.

引用

页码：22 / 26

页数：5

共 41 条

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