358972-72-2

Upstream product

• 358972-71-1 (3R,4S,5R,6R)-6-[N-benzyl-N-(benzyloxycarbonyl)amino]-3,4,5-tris(benzyloxy)-1,8-nonadiene 
• 501-53-1 benzyl chloroformate 
• 100-46-9 benzylamine 
• 291753-79-2 methyl 2,3,4-tri-O-benzyl-6-deoxy-6-iodo-α-D-manno-pyranoside 
• 358972-70-0 (3R,4S,5R,6R)-6-(N-benzylamino)-3,4,5-tris(benzyloxy)-1,8-nonadiene 

Downstream Products

• 358972-73-3 (2S,3R,4R,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.

Short syntheses of enantiopure calystegine B2, B3, and B4

Calystegine B2, B3, and B4 have been prepared in 5 steps from the benzyl protected methyl 6-iodoglycopyranosides of glucose, galactose and mannose, respectively, by using a zinc-mediated domino reaction followed by ring-cl