Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, PR China.
Org Biomol Chem. 2019 Apr 17;17(16):4061-4072. doi: 10.1039/c9ob00469f.
Gabosines and their natural analogues, belonging to C7 carbasugars, have attracted great attention in synthesis due to their rich structural variety and promising biological activities. A new diversity-oriented approach for the gabosine-type carbasugars based on a tunable regioselective aldol cyclization of flexible precursor 2 is explored. Two cyclization modes (A and B) of the precursor can be well controlled by switching promoters to selectively produce two resulting cyclohexa(e)nones 3 and 10, both of which are versatile intermediates for various C7 carbasugars. After the conversion of 3 to eight natural carbasugars, the utility of intermediate 10 is illustrated by the first synthesis of (-)-gabosine L, as well as the new synthesis of (-)-gabosine A, (-)-gabosine B, (-)-gabosine N and (-)-gabosine O. The chemical structure and the absolute configuration of (-)-gabosine L are confirmed by its total synthesis.
加博辛及其天然类似物属于 C7 碳环糖，由于其丰富的结构多样性和有前途的生物活性，在合成中引起了极大的关注。本文探索了一种基于可调区域选择性醛醇缩合的新型导向加博辛型碳环糖的多样性方法，该方法以灵活的前体 2 为基础。通过切换促进剂，可以很好地控制前体的两种环化模式（A 和 B），从而选择性地生成两种环己（e）酮 3 和 10，它们都是各种 C7 碳环糖的多功能中间体。3 转化为八种天然碳环糖后，通过 (-)-gabosine L 的首次全合成以及 (-)-gabosine A、(-)-gabosine B、(-)-gabosine N 和 (-)-gabosine O 的新合成，展示了中间体 10 的用途。(-)-gabosine L 的化学结构和绝对构型通过其全合成得到确认。
