Diversity oriented concise asymmetric synthesis of azasugars: a facile access to l-2,3-trans-3,4-cis-dihydroxyproline and (3S,5S)-3,4,5-trihydroxypiperidine.

Diversity oriented concise asymmetric syntheses of l -2,3- trans -3,4- cis -dihydroxyproline and (3 S ,5 S )-3,4,5-trihydroxypiperidine have been developed from ( R )-glycidol. The key step of the synthesis is Sharpless asymmetric dihydroxylation on enantiomerically pure TBDMS protected allylic alcohol 14 which generates the triol intermediate 15 in excellent de . The (2 R ,3 R ,4 S )-2,3-dihydroxypentanoate derivative 15 was subsequently converted to natural pyrrolidine azasugar 1 and non-natural piperidine azasugar 4 under cascade reaction conditions in good yields. [ABSTRACT FROM AUTHOR]