Synthesis of glycosides of 3-deoxy-4-thiopentopyranosid-2-uloses and their reduction products: 3-deoxy-4-thiopentopyranosides
作者:Marı́a Laura Uhrig、Oscar Varela
DOI:10.1016/s0008-6215(02)00292-6
日期:2002.11
Michael addition of common thiols to the enone system of (2S)-2-benzyloxy-2H-pyran-3(6H)-one (1) afforded the corresponding 3-deoxy-4-thiopentopyranosid-2-ulose derivatives (2-4). The reaction was highly diastereoselective, and the addition was governed by the quasiaxially disposed 2-benzyloxy substituent of the starting pyranone. As expected from the enantiomeric excess of 1 (ee > 86%) the corresponding
将常见的硫醇迈克尔加成到(2S)-2-苄氧基-2H-吡喃-3(6H)-一(1)的烯酮体系中,得到相应的3-脱氧-4-硫代戊吡喃二糖-2-ulose衍生物(2-4 )。该反应是高度非对映选择性的,并且加成由起始吡喃酮的准轴向设置的2-苄氧基取代基控制。如对映体过量1(ee> 86%)所预期的,相应的硫代果糖2-4显示出相同的光学纯度。然而,对映体纯的硫代果糖5是通过使1与手性硫醇N-(叔丁氧基羰基)-L-半胱氨酸甲酯反应而获得的。还通过6(1的对映异构体)与相同的手性硫醇反应合成了硫代衍生物7。或者,通过将硫醇1,4-加成至(2S)-[(S)-2'),以高光学纯度制备4-硫戊-2-酮9-12。-辛基氧基]二氢吡喃酮8。类似地,13(8的对映异构体)与苯甲硫醇的反应得到14(10的对映异构体)。这样,异头异构中心对起始的二氢吡喃酮施加的立体控制导致了D和L系列的4-硫代戊糖。硼氢化钠将乌糖10