substrate‐controlled diastereoselective switch strategy has been successfully developed. The [4+1] annulation of thioamides with sulfur ylides proceeded smoothly via a Michael addition triggered sequential process, and trans‐dihydrothieno[3,4‐c]coumarins were obtained because of steric hindrance effects between the benzoyl group and the unit of 2H‐chromen‐2‐one as shown in the Newman projection. Nucleophilic
已经成功地开发了一种实现新颖的,受底物控制的非对映选择性切换策略的便捷实用途径。
硫代酰胺与
硫醚的[4 + 1]环化通过迈克尔加成触发顺序过程顺利进行,由于苯甲酰基与2单元之间的位阻效应,获得了反式-二氢
噻吩并[3,4- c ]
香豆素。H -chromen-2-one,如纽曼投影所示。在[4 + 1]环空中,
硫代乙酰胺被
苯乙酮替代时,亲核取代被认为是关键步骤,并且两次π,π-堆积供体-受体相互作用稳定了导致顺式-dihydrothienono的过渡态[3]。 ,4- ç]
香豆素。此外,还研究了一种简单的
化学选择性反应,提供了一系列
噻吩并[3,4- c ]
香豆素。