72120-99-1

Upstream product

• 66537-92-6 methyl 2,3-anhydro-4,6-benzylidene-α-D-allopyranoside 
• 72079-87-9 4,6-O-benzylidene-2,3-dideoxy-2,3-C-isopropylidene-aldehydo-D-mannose 
• 72120-96-8 4,6-O-benzylidene-2,3-dideoxy-2,3-C-isopropylidene-D-glucose 
• 2605-68-7 methyl 2-(triphenylphosphoranylidene)propionate 
• 92464-12-5 methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-C--α-D-mannopyranoside 
• 72079-83-5 methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-C--α-D-mannopyranoside 
• 72079-85-7 methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-C--α-D-mannopyranoside 
• 72079-84-6 methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-C--α-D-mannopyranoside 
• 72079-86-8 methyl 4,6-O-(phenylmethylene)-2,3-dideoxy-2,3-C-isopropylidene-α-D-mannopyranoside 

Relevant academic research and scientific papers

ANNULATED PYRANOSIDES-V. AN ENANTIOSPECIFIC ROUTE TO (+) AND (-) CHRYSANTHENUM DICARBOXYLIC ACIDS.

Methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside undergoes the Wadsworth-Emmons cyclopropanation with phosphonopropionate to give a cyclopropyl carboxylate which is processed to give the gem-dimethylcyclopropano pyranoside.The glycosylic acetal of this substance is readily hydrolyzed by boiling water, and the resulting cis-cyclopropane carboxaldehyde may epimerized quantitatively to the trans-analog by treatment with sodium methoxide.These are now converted into the (+)- and (-)-chrysanthenum dicarboxylic acids, respectively, by the same sequence of reactions involving (a) olefination with methyl 2-(triphenylphosphoranylidene)propionate, (b) hydrolysis of the benzylidene ring and cleavage of the resulting triol with sodium metaperiodate, and (c) oxidation of the resulting aldehyde with silver I oxide.In the case of the (+)-enantiomer the last reaction is preceeded by epimerization.The overall yields from the D-allopyranoside are respectively 27percent, in 10 steps for the (+)-enantiomer, and 24percent, in 10 steps for the (-)-enantiomer, from the known epoxide 7.