First Experimental Evidence of an Intramolecular H Bond between Aliphatic Cl and Aromatic C–H
摘要:
The first example of an intramolecular H bond between aliphatic Cl and aromatic C H was observed in the crystal of C-2-symmetric (4R,5R)-4,5-bis(diphenylchloromethyl)-1,3,2-dioxathiolane 2-oxide. In this case one Cl atom is engaged in H-bonding with two ortho-C H groups in the axial and equatorial phenyl planes, with the recorded distances of 2.562 angstrom and 2.804 angstrom, respectively. The observed angle for Ca-H-Cl is 108.41 degrees and that. for C-q-H-Cl is 96.53 degrees.
of the chirogenic centers upon preparation of bioxirane derivatives takes place. Further methodology of the catalyst-free regiospecific transformation to enantiopure 1,3-oxazoline-2-thione derivatives has successfully been developed by coupling the bioxiranes with NH4SCN, which provides a new and facile access to different TADDOL derivatives.
开发了一种以天然酒石酸为原料合成(2 S ,2 'S )-3,3,3',3'-四芳基-2,2'-二环氧乙烷的新型实用方法。四步合成方案包括以下步骤:酒石酸的酯化、酒石酸酯的芳基化、高度区域选择性的 2,3-环亚硫酸化、(2 R ,3 R ) 的 1,4-氯化)-1,1,4,4-四芳基丁烷四醇与亚硫酰氯发生分子内环化反应。已证实在制备生物环氧乙烷衍生物时手性中心没有发生立体化学反转。通过将 bioxiranes 与 NH 4 SCN偶联,成功开发了无催化剂区域特异性转化为对映体纯 1,3-oxazoline-2-thione 衍生物的进一步方法,这为获得不同的 TADDOL 衍生物提供了一种新的、简便的途径。