Fischer Carbene Catalysis of Alkynol Cycloisomerization: Application to the Synthesis of the Altromycin B Disaccharide
作者:BonSuk Koo、Frank E. McDonald
DOI:10.1021/ol070435s
日期:2007.4.1
[reaction: see text] The tungsten-catalyzed cycloisomerization of alkynyl alcohols can be conducted without using photochemistry, using a stable tungsten Fischer carbene as the precatalyst for this transformation. A variety of alkynyl alcohols undergo cycloisomerization under these conditions to provide endocyclic enol ethers of five-, six-, and seven-membered ring sizes. The utility of this method is further
Stereoselective Synthesis of S-Linked Hexasaccharide of Landomycin A via Umpolung S-Glycosylation
作者:Kedar N. Baryal、Jianglong Zhu
DOI:10.1021/acs.orglett.5b02223
日期:2015.9.18
Stereoselectivesynthesis of carbohydrate mimics resistant toward acid-mediated or enzymatic hydrolysis is chemically challenging and biologically interesting. In this Letter, the first stereoselectivesynthesis of a “non-hydrolyzable” S-linked hexasaccharide of antitumor antibiotic landomycin A is described. This synthesis was accomplished through the utilization of our recently developed umpolung