Reductive Ring‐Opening Reaction of 1,2‐O‐Benzylidene and 1,2‐O‐p‐Methoxybenzylidene‐α‐D‐glucopyranose Using Diisobutyl Aluminum Hydride
摘要:
Regioselectivity in the reductive ring-opening reaction of 3,4,6-tri-O-benzyl-1,2-O-benzylidene and 3,4,6-tri-O-benzyl-1,2-O-p-methoxybenzylidene-alpha-D-glucopyranose using diisobutyl aluminum hydride (DIBAH) was examined. The ratio of the 1-O- and 2-O-p-methoxybenzyl ethers, which were generated from endo-type 1,2-O-p-methoxybenzylidene, was variable by the change of solvent.
An improved and practical synthesis of 1,2-O-benzylidene and 1,2-O-p-methoxybenzylidene hexopyranoses as useful synthons in carbohydrate chemistry is described. The reaction of 2-benzoyloxyglycosyl bromide with sodium borohydride using excess amount of potassium iodide proceeded smoothly to give the corresponding 1,2-O-benzylidene derivative in good yields.
Reductive Ring‐Opening Reaction of 1,2‐<i>O</i>‐Benzylidene and 1,2‐<i>O</i>‐<i>p</i>‐Methoxybenzylidene‐α‐<scp>D</scp>‐glucopyranose Using Diisobutyl Aluminum Hydride
Regioselectivity in the reductive ring-opening reaction of 3,4,6-tri-O-benzyl-1,2-O-benzylidene and 3,4,6-tri-O-benzyl-1,2-O-p-methoxybenzylidene-alpha-D-glucopyranose using diisobutyl aluminum hydride (DIBAH) was examined. The ratio of the 1-O- and 2-O-p-methoxybenzyl ethers, which were generated from endo-type 1,2-O-p-methoxybenzylidene, was variable by the change of solvent.
Regioselectivity in the reductive ring-opening reaction of 1,2-O-benzylidene sugars
Regioselectivity in the ring-opening reaction of 1,2-O-benzylidene sugars was studied. In the reductivering-opening reaction of 1,2-O-benzylidene derivatives, only a CO1 bond was cleaved in the case of manno-type, but both the CO1 and CO2 bonds were cleaved in the case of gluco-type.
研究了1,2- O-亚苄基糖在开环反应中的区域选择性。在1,2- O-亚苄基衍生物的还原性开环反应中,在甘露型的情况下,仅C 1 O 1键被断裂,而在C 2 O 1和C 3 O 2键均被断裂。葡萄糖型的情况。