Construction of an Optically Active 7-Oxabicyclo[4.3.0]non-4-en-3-one Skeleton from D-Glucose, and Its Transformation to Some Pseudo-Hexopyranoses
作者:Kin-ichi Tadano、Yoshihide Ueno、Chiyoko Fukabori、Yukinori Hotta、Tetsuo Suami
DOI:10.1246/bcsj.60.1727
日期:1987.5
A versatile chiral compound, (1R,6R,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]non-4-en-3-one (6), was efficiently synthesized from d-glucose. The synthesis featured an intramolecular aldol cyclization of 3-C-acetylmethyl-3-deoxy-1,2-O-isopropylidene-α-d-ribo-pentodialdo-1,4-furanose, which was readily derivatized from the known Wittig adducts of 1,2:5,6-di-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose. The utility of this highly functionalized chiral synthon 6 was embodied by conversion to four optically active pseudosugars, these are pentaacetyl derivatives of pseudo-α-l-altropyranose, pseudo-β-d-glucopyranose, pseudo-2-amino-2-deoxy-β-l-altropyranose, and pseudo-2-amino-2-deoxy-α-d-glucopyranose (a derivative of pseudoglucosamine). The transformation of 6 to the pseudo sugars involved 1) a stereospecific epoxidation of the double bond in 6 providing (1R,4S,5S,6S,8R,9R)-4,5-epoxy-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonan-3-one (8), and 2) an exclusive diaxial ring opening of the β-epoxy alcohols, which were derived from 8, providing (1R,3R,4S,5S,6S,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonane-3,4,5-triol (11) or (1R,3S,4S,5R,6S,8R,9R)-4-azido-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonane-3,5-diol. Treatment of (1R,2S,3S,4S,5R)-3,4,5-tris(benzyloxy)-2-hydroxycyclohexanecarbaldehyde, which was derived from 11, with methanesulfonyl chloride, and successive sodium borohydride reduction provided (3S,4S,5R)-3,4,5-tris(benzyloxy)-1-cyclohexene-1-methanol (19). Hydroboration of 19 proceeded from the less hindered side stereoselectively.
以 d-
葡萄糖为原料,高效合成了一种多功能手性化合物 (1R,6R,8R,9R)-8,9-异丙叉二
氧基-7-
氧杂二环[4.3.0]non-4-en-3-one (6)。该合成以 3-C-乙酰
甲基-3-
脱氧-1,2-O-异丙叉-α-d-
核糖-
戊二醛-1,4-
呋喃糖的分子内羟醛环化为特征,很容易从已知的 Wittig 加合物衍生而来1,2:5,6-二-O-异亚丙基-α-d-
核糖-六
呋喃-3-乌糖。这种高度功能化的手性合成子 6 的实用性通过转化为四种光学活性假糖来体现,它们是假-α-L-
吡喃
丙醇糖、假-β-d-
吡喃
葡萄糖、假-2-
氨基-2-
脱氧-的五乙酰衍
生物。 β-l-
吡喃丙糖和假-2-
氨基-2-
脱氧-α-d-
吡喃
葡萄糖(假
葡萄糖胺的衍
生物)。 6 向假糖的转化涉及 1) 6 中双键的立体特异性环
氧化,提供 (1R,4S,5S,6S,8R,9R)-4,5-环
氧-8,9-异丙叉二
氧基-7-
氧杂双环[4.3.0]壬南-3-
酮 (8),和 2) β-环
氧醇的独特双轴开环,衍生自 8,提供 (1R,3R,4S,5S,6S,8R,9R )-8,9-异丙叉二
氧基-7-
氧杂二环[4.3.0]
壬烷-3,4,5-三醇(11)或(1R,3S,4S,5R,6S,8R,9R)-4-
叠氮基-8 ,9-异丙叉二
氧基-7-
氧杂双环[4.3.0]
壬烷-3,5
-二醇。用甲
磺酰氯处理衍生自11的(1R,2S,3S,4S,5R)-3,4,5-三(苄
氧基)-2-羟基
环己烷甲醛,并连续进行
硼氢化钠还原,得到(3S,4S, 5R)-3,4,5-三(苄
氧基)-1-
环己烯-1-
甲醇(19)。 19的
硼氢化反应从受阻较小的一侧立体选择性地进行。