Advances in C-alkynylation of sugars and its application in organic synthesis
Abstract
C-Glycosidation plays a significant role in the synthesis of optically active scaffolds. Among C-glycosylations, C-alkynylation has emerged as a synthetic tool in organic or natural product synthesis since it make use of carbohydrates as chiral pool and source of carbon as well. In this present review several modes of C-alkynyl-glycosylations have been summarized based on different glycosyl donors such as glycals, anomeric acetates, anomeric halosugars, 1,2-anhydrosugars, 1,6-anhydrosugars, lactones, lactols and activated/unactivated terminal alkynes as a glycan partner under various Lewis acids like TiCl4, I2, BF3·OEt2, Cu(OTf)2, TMSOTf and/or metals like In, Zn. Further, total/fragment stereoselective synthesis of some important natural products has been elaborated.