Asymmetric synthesis of (−)- and (+)-neodichroine/hydrachine A from (+)- and (−)-febrifugine
作者:Shaun Smullen、Paul Evans
DOI:10.1016/j.tetlet.2018.03.035
日期:2018.4
asymmetric approach to both enantiomers of the quinazolinone-containing natural product febrifugine is reported. Utilising a proline-mediated aminooxylation-Horner-Wadsworth-Emmons sequence provides the key optically active 2,3-disubstituted piperidine intermediate 7 in high enantioselectivity but poor overall yield (7 steps, 3%, 98% ee). This intermediate has been used to prepare both naturally occurring
报道了一种新的不对称方法,该方法对含有喹唑啉酮的天然产物非博古丁的两种对映异构体进行了研究。利用脯氨酸介导的氨氧基化-Horner-Wadsworth-Emmons序列可提供关键的光学活性的2,3-二取代哌啶中间体7,具有高对映选择性,但总收率较差(7步,3%,98%ee)。该中间体已被用于制备天然存在的(+)-非溴夫定(1)及其(-)-对映体。继而,每种化合物随后又被用于首次合成所要求保护的天然产物新二鱼氨酸/水合素A的两种对映异构体。合成化合物的光谱数据与所要求保护的结构相匹配。但是,比旋转与隔离工作在大小和符号上都不同。