106988-72-1

Upstream product

• 108-22-5 Isopropenyl acetate 
• 117249-16-8 1,5-anhydro-2,6-dideoxy-4-O-(phenylmethyl)-L-arabino-hex-1-enitol 
• 108-24-7 acetic anhydride 
• 106988-70-9 1,5-Anhydro-4-O-benzyl-2,6-dideoxy-L-ribo-hex-1-enitol 

Downstream Products

• 158021-40-0 benzyl 4-O-benzyl-3-O-(4-O-benzyl-2,6-dideoxy-α-L-ribopyranosyl)-2,6-dideoxy-α-L-ribo-hexopyranoside 
• 158021-38-6 benzyl 3-O-(3-O-acetyl-4-O-benzyl-2,6-dideoxy-2-iodo-α-L-altropyranosyl)-4-O-benzyl-2,6-dideoxy-α-L-ribo-hexopyranoside 

Relevant academic research and scientific papers

Epimerization of glycal derivatives by a cyclopentadienylruthenium catalyst: Application to metalloenzymatic DYKAT

Epimerization of a non-anomeric stereogenic center in carbohydrates is an important transformation in the synthesis of natural products. In this study an epimerization procedure of the allylic alcohols of glycals by cyclopentadienylruthenium catalyst 1 is presented. The epimerization of 4,6-O-benzylidene-d-glucal 4 in toluene is rapid, and an equlibrium with its d-allal epimer 5 is established within 5 min at room temperature. Exchange rates for allal and glucal formation were determined by 1D 1H EXSY NMR experiments to be 0.055 s-1 and 0.075 s -1, respectively. For 4-O-benzyl-l-rhamnal 8 the epimerization was less rapid and four days of epimerization was required to achieve equilibration of the epimers at room temperature. The epimerization methodology was subsequently combined with acylating enzymes in a dynamic kinetic asymmetric transformation (DYKAT), giving stereoselective acylation to the desired stereoisomers 12, 13 , and 15. The net effect of this process is an inversion of a stereogenic center on the glycal, and yields ranging from 71% to 83% of the epimer were obtained.

Syntheses of Selectively Alkylated Enol Ethers in the L-ribo Series

The reduction of enulose 1a predominantly leads to L-digitoxal (3a), although this method presents a sluggish reaction with moderate yields.In contrast, the preparation from L-digitoxose (4a) in a three-step one-pot procedure represents an advantageous approach.Regioselective 3- or 4-O-alkylations are achieved by phase-transfer catalysis method or via stannylidene intermediates to give monosaccharide precursors of the L-ribo series valuable for further interglycosidic linking.