作者:Hui Yao、Shasha Zhang、Wei-Lin Leng、Min-Li Leow、Shaohua Xiang、Jingxi He、Hongze Liao、Kim Le Mai Hoang、Xue-Wei Liu
DOI:10.1021/acscatal.7b01630
日期:2017.8.4
Stereoselective construction of various O-glycosidic bonds was first achieved by different palladium sources using 3,4-O-carbonate galactal as the donor to reach yields up to 95% under mild conditions. With Pd(II) catalyst coordination of this glycal donor from the β-face directed by carbonate group, hard nucleophiles (aliphatic alcohols) gave β-glycosides and α-glycosides were obtained from soft nucleophiles
各种O-糖苷键的立体选择性构建首先是通过使用3,4- O-碳酸半乳糖作为供体,通过不同的钯源实现的,在温和的条件下,收率可达95%。用Pd(II)催化剂从由碳酸酯基团定向的β面配位该糖基供体,硬的亲核试剂(脂族醇)得到β-糖苷,而α-糖苷则从软的亲核试剂(苯酚)制得。相比之下,由于空间效应,Pd(0)催化剂从β面上配位给体,硬受体和软受体都只能通过氢键介导的糖苷配基生成β-糖苷。