Synthesis and Configurational Assignment of Chiral Salicylic Aldehydes: Novel Building Blocks for Asymmetric Catalysis
作者:Albrecht Berkessel、Matthias R. Vennemann、Johann Lex
DOI:10.1002/1099-0690(200208)2002:16<2800::aid-ejoc2800>3.0.co;2-4
日期:2002.8
condensation of the racemic salicylic aldehydes with (R)-phenylglycinol. Finally, the absolute configurations of two of the salicylic aldehydes were established by X-ray crystallography. For this purpose, the (1-phenylethyl)-substituted salicylic aldehyde was condensed with L-valinamide, and the relative configuration of the resulting Schiff base diastereomer 12 was determined. In the second case, the racemic
我们报告了三个新颖的和手性的水杨醛结构单元6-8的合成,每个都以对映体纯形式存在。这些水杨醛中的两个是从(+)-camp烯制备的,每个都带有一个与水杨酸羟基邻位的[2.2.1]双环庚基取代基。在第三种情况下,在6-位的手性元素是(1-苯乙基)基团。合成序列由的邻位的烷基化对位与任一莰或苯乙烯和随后的甲苯酚邻产物苯酚的-formylation。对映体的色谱分离是通过将外消旋水杨醛与(R)-苯基甘氨醇。最后,通过X射线晶体学确定了两个水杨醛的绝对构型。为此目的,将(1-苯乙基)-取代的水杨醛与L-缬氨酰胺缩合,并且确定所得的席夫碱非对映异构体12的相对构型。在第二种情况下,外消旋中间体苯酚rac - 15在手性固定相上通过HPLC分离,邻位溴化,并通过反常X射线散射进行分析。(©Wiley-VCH Verlag GmbH,69451 Weinheim,Germany,2002)