Diastereoselective Aldol Reactions of Furaldehyde Using a Chiral Boronate as Auxiliary: Application to the Synthesis of Enantiomerically Pure and Highly Functionalized 2,3-Disubstituted Furanyl Alcohols
作者:Kin-Fai Chan、Henry N. C. Wong
DOI:10.1002/1099-0690(200301)2003:1<82::aid-ejoc82>3.0.co;2-x
日期:2003.1
column chromatography on silica gel, leading to optically pure aldol adducts. The absolute stereochemistry of the aldol adducts were determined by X-ray crystallographic analysis. Further transformation of the carbon−boron bond to a carbon−carbon bond was achieved in a Suzuki coupling reaction to furnish highly functionalized and enantiomerically pure 2,3-disubstituted furyl alcohols. One of the furyl alcohols
已经研究了各种乙烯酮甲硅烷基缩醛或烯醇锂与呋喃醛2的醛醇缩合反应。呋喃醛2在呋喃C-3位置带有一个手性硼酸酯基。发现(R)非对映选择性比(S)更有利。)获得了非对映选择性和中等非对映选择性。通过简单的快速硅胶柱色谱可色谱分离某些生成的羟醛非对映异构体,从而得到光学纯的羟醛加合物。通过X射线晶体学分析确定了羟醛加合物的绝对立体化学。在Suzuki偶联反应中,碳硼键进一步转变为碳碳键,以提供高度官能化和对映体纯的2,3-二取代呋喃醇。为了证实该方法的有效性,使一种呋喃醇重排为羟基吡喃酮。(©Wiley-VCH Verlag GmbH&Co.KGaA,69451 Weinheim,Germany,2003)