(S,S)-alpha,alpha'-Diamino-1,4- and 1,3-benzenediacetic acids and N-Boc- and N-Fmoc-derivatives have been prepared by stereoselective syntheses. The chiral auxiliary (S)-4-benzyl-2-oxazolidinone formed bisimides with benzenediacetyl dichlorides The imides were lithiated at both a-sites to the carbonyl groups and azidated stereoselectively alpha to both carbonyl groups by trisyl azide to provide (S,S)-alpha,alpha'-diazidobenzenediacetic acid derivatives which were reduced to amines by Sn(II) chloride or by hydrogenolysis over Pd. Copyright (C) 1996 Elsevier Science Ltd
Silacyclophanones – cyclic organosilicon esters of isophthalic acid
作者:Sergey V. Basenko、Anastasiya S. Soldatenko
DOI:10.1007/s10593-018-2239-5
日期:2018.1
of previously unknown 16-membered cyclicorganosilicon esters of isophthalic acid (silacyclophanones) in 69–77% yields. The reaction of isophthalic ester with 1,3-dichloro-1,3-dimethyl-1,3-divinyldisiloxane gave 14-membered cyclosiloxane ester as the main product, while the reaction of disiloxane with trimethylsilyl ester of phthalic acid produced a 9-membered cyclic ester in 65% yield.