332178-29-7

Upstream product

• 73111-58-7 2,3,4-tri-O-benzyl-5,6-dideoxy-D-xylo-hex-5-enose 
• 100-46-9 benzylamine 
• 358972-61-9 (3R,4S,5S,6R)-6-[N-benzyl-N-(benzyloxycarbonyl)amino]-3,4,5-tris(benzyloxy)-1,8-nonadiene 
• 358972-59-5 (3R,4S,5S,6R)-6-(N-benzylamino)-3,4,5-tris(benzyloxy)-1,8-nonadiene 
• 501-53-1 benzyl chloroformate 
• 85716-43-4 methyl 6-deoxy-6-iodo-2,3,4-tri-O-benzyl-α-D-glucopyranoside 
• 332178-28-6 (3R,4S,5S,6R)-6-[N-benzyl-N-(benzyloxycarbonyl)amino]-3,4,5-tris(benzyloxy)cycloheptene 

Downstream Products

• 332178-31-1 (2S,3R,4S,5R)-5-[N-benzyl-N-(benzyloxycarbonyl)amino]-2,3,4-tris(benzyloxy)cycloheptanone 

Relevant academic research and scientific papers

A short synthetic route to the calystegine alkaloids

An efficient strategy is described for the synthesis of enantiopure calystegine alkaloids. The key step employs a zinc-mediated fragmentation of benzyl-protected methyl 6-iodo-glycosides followed by in situ formation of the benzyl imine and Barbier-type allylation with zinc, magnesium, or indium metal. Stereochemistry in the pivotal allylation is controlled by the choice of the metal. The functionalized 1,8-nonadienes, thus formed, are converted into cycloheptenes by ring-closing olefin metathesis. Regioselective hydroboration and oxidation give the corresponding cycloheptanones, which are deprotected to afford the desired calystegines. Hereby, calystegine B2, B3, and B4 are prepared from D-glucose, D-galactose, and D-mannose, respectively. This route constitutes the shortest synthesis of calystegine B2 and gives rise to the first total syntheses of calystegine B3 and B4.

A short and efficient synthesis of (+)-calystegine B2

A short synthesis of (+)-calystegine B2 from (D)-glucose has been achieved, which involves as the key step a triple domino zinc-mediated reductive ring-opening, imine formation and allylation reaction of 6-iodoglucopyranose.