99701-79-8Relevant academic research and scientific papers
Investigations of scope and mechanism of nickel-catalyzed transformations of glycosyl trichloroacetimidates to glycosyl trichloroacetamides and subsequent, atom-economical, one-step conversion to α-urea-glycosides
McKay, Matthew J.,Park, Nathaniel H.,Nguyen, Hien M.
supporting information, p. 8691 - 8701 (2014/07/21)
The development and mechanistic investigation of a highly stereoselective methodology for preparing α-linked-urea neo-glycoconjugates and pseudo-oligosaccharides is described. This two-step procedure begins with the selective nickel-catalyzed conversion of glycosyl trichloroacetimidates to the corresponding α-trichloroacetamides. The α-selective nature of the conversion is controlled with a cationic nickel(II) catalyst, [Ni(dppe)(OTf)2] (dppe=1,2-bis(diphenylphosphino)ethane, OTf=triflate). Mechanistic studies have identified the coordination of the nickel catalyst with the equatorial C2-ether functionality of the α-glycosyl trichloroacetimidate to be paramount for achieving an α-stereoselective transformation. A cross-over experiment has indicated that the reaction does not proceed in an exclusively intramolecular fashion. The second step in this sequence is the direct conversion of α-glycosyl trichloroacetamide products into the corresponding α-urea glycosides by reacting them with a wide variety of amine nucleophiles in presence of cesium carbonate. Only α-urea-product formation is observed, as the reaction proceeds with complete retention of stereochemical integrity at the anomeric C-N bond.
Stereoselective rearrangement of trichloroacetimidates: application to the synthesis of α-glycosyl ureas
Park, Nathaniel H.,Nguyen, Hien M.
supporting information; experimental part, p. 2433 - 2436 (2009/11/30)
A new method for the stereoselective synthesis of r-glycosyl ureas, via nickel-catalyzed [1,3]-rearrangement of glycosyl trichloroacetimidates, has been developed. The r-stereoselectivity at the anomeric carbon of the resulting trichloroacetamides depends
O-Glycosyl Imidates, 19. - Reactions of Glycosyl Trichloroacetimidates with Silylated C-Nucleophiles
Hoffmann, Michael G.,Schmidt, Richard R.
, p. 2403 - 2419 (2007/10/02)
Reaction of O-benzyl-protected α-glycopyranosyl trichloroacetimidates 1 and the xylo analogues 7 with silyl enol ethers or allyltrimethylsilane as C-nucleophiles yields with zink chloride as catalyst mainly or exclusively α-C-glycosides (5a-α to 5h-α, 8b,
