Highly stereoselective synthesis of 3-amino-3,6-dideoxy-aldohexoses by tin triflate mediated aldol condensation reaction of tricarbonyl iron α-aminodienone complexes. Total synthesis of multiprotected mycosamine

✍ Scribed by Michel Franck-Neumann; Laurence Miesch-Gross; Christelle Gateau

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 244 KB
• Volume: 40
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(99)00271-3

✦ Synopsis

The divalent tin enol ether of the racemic N-BOC ot-aminodienone tricarbonyliron complex 4 reacts with both enantiomers of protected lactaldehydes to predominantly yield one optically active ketol diastereoisomer (45 %). From the enantiomerically pure complex (S).(+)-4 and (R)-(+) tert butyldimethylsilyloxylactaldehyde this ketol is obtained almost alone (isolated 86 %). From there, the multi-protected 3-amino-3,6-dideoxy-D-aldohexose mycosamine is obtained in a few high yielding steps (decomplexation, stereospecific reduction to a 1,3-diol, transformation into a diacetate and ozonolysis ; absolute configurations S,S,S,R). By reduction of the ketol before decomplexation, the stereochemistry of the reaction is completely reversed (control by the Fe(CO) 3 and not by the hydroxyl group), giving also access to the R,S,S.R series. (Structures determined by X-ray diffraction).