Six-Step Syntheses of (−)-1-Deoxyaltronojirimycin and (+)-1-Deoxymannonojirimycin from N-Z-O-TBDPS-l-serinal

Abstract

Highly stereoselective six-step syntheses of (-)-1-deoxyaltronojirimycin (altro-DNJ) and (+)-1-deoxymannojirimycin (manno-DNJ) from N-Cbz-O-TBDPS-l-serinal are described. Key transformations involve a two-step preparation of a functionalized dihydropyridin-3-one as a common intermediate followed by Luche reduction and dihydroxylation (for altro-DNJ). The same sequence employing an epoxidation/epoxide opening in place of dihydroxylation furnishes manno-DNJ.

Synthesis of Penta-2,4-dien-1-imines and 1,2-Dihydropyridines by Rhodium-Catalyzed Reaction of N-Sulfonyl-1,2,3-triazoles with 2-(Siloxy)furans

“…The products would be valuable intermediates for the synthesis of polysubstituted piperidines, 9 such as aza sugars. 10 Initially, 4-phenyl-1-tosyl-1,2,3-triazole (1a) was prepared from phenylacetylene and tosyl azide according to Fokin's procedure 11 using copper(I) thiophene-2-carboxylate (CuTC). Then the isolated triazole 1a (0.2 mmol) was treated with 2-(triisopropylsiloxy)furan (2a) (1.5 equiv) in chloroform at 70 °C in the presence of 1.0 mol % Rh 2 (esp) 2 (esp = α,α,α′,α′tetramethyl-1,3-benzenedipropionate) 12 and 4 Å molecular sieves (MS) (Table 1, entry 1).…”

“…We now report that either open-chain penta-2,4-dien-1-imines or cyclic 1,2-dihydropyridines, not pyrrole derivatives, are selectively obtained by a rhodium­(II)-catalyzed reaction of N -sulfonyl-1,2,3-triazoles with 2-(siloxy)­furans. The products would be valuable intermediates for the synthesis of polysubstituted piperidines, such as aza sugars …”

Organocatalytic Enantioselective Sulfa-Michael Additions to α,β-Unsaturated Diazoketones

“…To further demonstrate the synthetic utility of the present methodology, the disubstituted tetrahydrothiophene 5 was synthesized (Scheme C). Sulfa-Michael product 3a was refluxed in toluene with Cu­(acac) 2 (10 mol %) , to afford the Stevens rearrangement product 5 with 49% yield (isolated yield for the major diastereoisomer) (94% ee ) + its diastereomer (2:1 dr ).…”

Recent advances in the total synthesis of polyhydroxylated alkaloids via chiral oxazines

“…(+)-1-Deoxynojirimycin ((+)-DNJ, 2 ), 65,84,102,103 (+)-1-deoxygalactonojirimycin ((+)- galacto -DNJ, 3 ), 8,77,104 (−)-1-deoxygulonojirimycin ((−)- gulo -DNJ, 4 ), 10,104 e , f ,105 and (−)-1-deoxymannojirimycin ((+)- manno -DNJ, 5 ) 65,82,104 g ,106 are reduced analogues of (+)-nojirimycin ( N2 , Fig. 1), which is also an N -substituted analogue of d -glucose.…”