215360-97-7

Upstream product

• 626-15-3 1,3-bis-(bromomethyl)benzene 
• 39483-51-7 ethyl 2,3,4-tri-O-benzyl-1-thio-β-D-glucopyranoside 
• 215360-88-6 ethyl 2,3,4-tri-O-benzyl-6-O-(3-bromomethylbenzyl)-1-thio-β-D-glucopyranoside 
• 17791-36-5 methyl 2,3-di-O-benzyl-α-D-glucopyranoside 

Downstream Products

• 744-05-8 methyl 4-O-β-D-glucopyranosyl-(1->4)-α-D-glucopyranoside 
• 215361-01-6 methyl 6,6'-O-(1,3-xylylene)-(2,3,4-tri-O-benzyl-β-D-glucopyranosyl)-(1'->4)-2,3-di-O-benzyl-α-D-glucopyranoside 

Relevant academic research and scientific papers

Intramolecular glycoside bond formation - A rigid spacer concept for the diastereoselective linkage between glycosyl donor and acceptor

α,α-Dibromo-m-xylene gave compounds 5a,b and 7 which contain a glycosyl donor and acceptor moiety. Activation of 5a,b with NIS/TMSOTf as promoter system afforded β(1-4)-linkage leading to 6 as the only monomeric reaction product. Activation of 7 led also to β(1-4)-linkage affording 8 in very high yield.

Efficient Intramolecular Glycosylation Supported by a Rigid Spacer

The m-xylylene moiety was employed as rigid spacer in intramolecular glycoside bond formation. Fifteen-membered macrocycle formation starting from 6-O-linked donor and 6- and 4-O-linked acceptor (5a,b, 6b) led exclusively to β(1-4)- and β(1-6)-linked compounds 7β and 8β, respectively, which gave cellobioside and gentiobioside derivatives. The glycosylation yields could be improved by 14-membered macrocycle formation. In the four cases studied, the donor was 6-O-linked to the spacer. For the acceptor linkage to the spacer and the accepting hydroxy group, relative D-/L-threo- and D-/L-erythro-arrangements were chosen. Standard glycosylation conditions led in three cases (13, 14, 23) only to β-linkage in high yield (16β, 17β, 25β). For the transformation of 24, having a D-erythro-arrangement in the acceptor moiety, the α-anomer 26α was preferentially obtained. Limitation of the conformational space of the donor and the acceptor as in 31, which is stereochemically identical with 24, led to the corresponding α-glycoside 32α in 87% yield. Synthesis of a pseudo mirror image of 23 [having 6-(D)/3-(D-threo)-arrangement], namely 35, having 3(L)/6-(L-threo)-arrangement of the donor and acceptor moieties, expectedly gave only α-glycoside 36α in very high yield. Thus, the efficiency and versatility of this conceptual approach to intramolecular glycoside bond formation is exhibited.