Stereoselective synthesis of cyclobutyl α-aminocyclopropyl carboxylic acid derivatives
作者:A.G. Moglioni、E. Garcı́a-Expósito、A. Alvarez-Larena、V. Branchadell、G.Y. Moltrasio、R.M. Ortuño
DOI:10.1016/s0957-4166(00)00470-5
日期:2000.12
The highly stereoselective cyclopropanation of chiral cyclobutyl dehydro amino acids, synthesized from (−)-α-pinene or (−)-verbenone, has been achieved by means of a 1,3-dipolar cycloaddition with diazomethane. The proximity of the double bond to the neighbouring stereogenic center of the cyclobutyl moiety is crucial to obtain cyclopropanes as single diastereomers whose configuration has been determined
由(-)-α-pine烯或(-)-马来酮合成的手性环丁基脱氢氨基酸的高度立体选择性环丙烷化已通过重氮甲烷与1,3-偶极环加成反应实现。双键与环丁基部分的相邻立体异构中心的接近对于获得作为单一非对映体的环丙烷是至关重要的,其构型已通过X射线结构分析确定。通过DFT对更稳定构象的理论计算,我们可以了解π面非对映选择,这是由宝石-二甲基取代基和环丁烷环侧链引起的空间位阻的结果。已通过ORD和CD技术研究了这些产品的手性,并确定了它们在CSA-NMR实验中的行为。