Synthesis of 4-Deoxy-l-(and d-)hexoses from Chiral Noncarbohydrate Building Blocks
摘要:
4-Deoxy-L-hexoses were synthesized starting from our previously reported reagent 1 and (R)-benzyl glycidyl ether, which led in few steps to a substituted dihydropyran 6. The stereocontrolled hydroxylation of the latter afforded the corresponding 4-deoxy-L-hexoses 7a, 9, and 11. The same procedure, starting from (S)-benzyl glycidyl ether, enabled the preparation of their D-series enantiomers.
Synthesis of 4-Deoxy-l-(and d-)hexoses from Chiral Noncarbohydrate Building Blocks
摘要:
4-Deoxy-L-hexoses were synthesized starting from our previously reported reagent 1 and (R)-benzyl glycidyl ether, which led in few steps to a substituted dihydropyran 6. The stereocontrolled hydroxylation of the latter afforded the corresponding 4-deoxy-L-hexoses 7a, 9, and 11. The same procedure, starting from (S)-benzyl glycidyl ether, enabled the preparation of their D-series enantiomers.
The high-pressure [4+2]cycloaddition of 1-methoxybuta-1,3-diene to the glycolaldehyde-derived heterodienophiles, catalyzed by chiral metallosalen complexes
A high-pressure (ca. 10 kbar) reaction of 1-methoxybuta-1,3-diene 1 with variously O-protected glycolaldehydes 2, catalyzed by the chiral (salen)Cr(III)Cl 4a–d and 5 or (salen)Co(II) 6a–f and 7 complexes, has been studied. The best results were obtained for tert-butyldimethylsilyloxyacetaldehyde 2a. The reaction afforded, in good yield (up to 90%) and with very good diastereoselectivity (up to 92%)