Modulating the propeller-like shape of a tripodal C(CH2PPh2)3 fragment by the size of the substituent at the pivotal carbon atom in macrobicyclic tri-λ5-phosphazenes

被引：10

作者：

Alajarin, Mateo ^{[1
]}

Lopez-Leonardo, Carmen ^{[1
]}

Berna, Jose ^{[1
]}

机构：

[1] Univ Murcia, Fac Quim, Dept Quim Organ, E-30100 Murcia, Spain

来源：

TETRAHEDRON | 2007年 / 63卷 / 21期

关键词：

triphosphazides; tri-lambda(5) -phosphazenes; macrobicycles; cage compounds; propellers; tripod-tripod coupling;

D O I：

10.1016/j.tet.2007.03.076

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The chiral macrobicyclic tri-lambda(5)-phosphazenes formed by tripod-tripod coupling of tris(3-azidobenzyl)amines and 1,1,1-tris-[(diphenylphosphino)methyl]methanes present helical topologies as a result of combining two propeller-shaped tripodal fragments with the same sense of twist. The introduction of a series of R-piv substituents of increasing size at the pivotal carbon of the lower tert-butane fragment R-piv-QCH(2)PPh(2))(3) causes a gradual decrease of the helicity in the lower propeller. This phenomenon is revealed in their CDCl3 solution NMR spectra, and the activation energies for the racemization process of the tri-lambda(5)-phosphazenes were calculated by coalescence VT-NMR experiments. (C) 2007 Elsevier Ltd. All rights reserved.

引用

页码：4450 / 4458

页数：9

共 44 条

[1] Ab initio SCF-MO study of the Staudinger phosphorylation reaction between a phosphane and an azide to form a phosphazene [J].