130130-72-2

Upstream product

• 97-30-3 methyl-alpha-D-glucopyranoside 
• 1125-88-8 benzaldehyde dimethyl acetal 
• 3282-30-2 pivaloyl chloride 
• 104758-89-6 methyl 4,6-O-benzylidene-2-O-pivaloyl-α-D-glucopyranoside 

Downstream Products

• 130130-73-3 Methyl 4,6-O-benzylidene-3-C-(methoxycarbonylmethylene)-3-deoxy-2-O-pivaloyl-α-D-ribo-hexopyranoside 

Relevant academic research and scientific papers

Wittig Reaction: Domino Olefination and Stereoselectivity DFT Study. Synthesis of the Miharamycins' Bicyclic Sugar Moiety

2-O-Acyl protected-d-ribo-3-uloses reacted with [(ethoxycarbonyl)methylene]triphenylphosphorane in acetonitrile to afford regio- and stereoselectively 2-(Z)-alkenes in 10-60 min under microwave irradiation. This domino reaction is proposed to proceed via tautomerization of 3-ulose to enol, acyl migration, tautomerization to the 3-O-acyl-2-ulose, and Wittig reaction. Alternatively, in chloroform, regioselective 3-olefination of 2-O-pivaloyl-3-uloses gave (E)-alkenes, key precursors for the miharamycins' bicyclic sugar moiety.

The 'Off-template' Problem: Towards a General Solution

Wittig reaction of the t-butyldimethylsilylated C-3 ketone methyl 4,6-O-benzylidene-2-O-(t-butyldimethylsilyl)-α-D-ribo-hexopyranosid-3-uloside leads exclusively to C-2 alkenes, providing an efficient synthesis of these potentially useful intermediates.Alternatively, the corresponding t-butyldiphenylsilyl ether, prepared with complete regiospecificity from methyl 4,6-O-benzylidene-α-D-glucopyranoside, gives a C-3 alkene on oxidation and Wittig reaction.Deprotection, hydrogenation and cyclization of this product leads to the cis-fused butyrolactone, methyl 4,6-O-benzylidene-3-deoxy-3-(ethoxycarbonyl)-2,3-butyrolactone-α-D-allopyranoside, which is alkylated stereospecifically to give methyl 4,6-O-benzylidene-3-deoxy-3-(prop-2-yloxycarbonyl)-2,3-butyrolacto-α-D-allopyranoside.This procedure provides a general solution of the 'off-template' problem of carbohydrate-based natural product synthesis.