2-[(1R,3R,3aR,3bS,6R,6aR,6bS)-3-(2-Methoxy-ethoxymethoxy)-3a,6-dimethyl-decahydro-cyclobutadicyclopenten-1-yl]-malonic acid dimethyl ester | 132294-43-0

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: 2-[(1R,3R,3aR,3bS,6R,6aR,6bS)-3-(2-Methoxy-ethoxymethoxy)-3a,6-dimethyl-decahydro-cyclobutadicyclopenten-1-yl]-malonic acid dimethyl ester
• CAS: 132294-43-0
• 化学式: C₂₁H₃₄O₇
• 分子量: 398.497
• InChiKey: RBDRQBUFXZCKDP-ONYQJRPDSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.27
• 重原子数：
  28.0
• 可旋转键数：
  9.0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.9
• 拓扑面积：
  80.29
• 氢给体数：
  0.0
• 氢受体数：
  7.0

反应信息

• 作为产物：
  描述：

  dimethyl 2-[(1R,2R,3S,5R,6R,7S,10R)-5-(2-methoxyethoxymethoxy)-6,10-dimethyl-3-tricyclo[5.3.0.02,6]decanyl]-2-phenylselanylpropanedioate 在 sodium tetrahydroborate 、 双氧水 作用下， 以 乙醇 、 二氯甲烷 为溶剂， 反应 10.0h， 生成 2-[(1R,3R,3aR,3bS,6R,6aR,6bS)-3-(2-Methoxy-ethoxymethoxy)-3a,6-dimethyl-decahydro-cyclobutadicyclopenten-1-yl]-malonic acid dimethyl ester
  参考文献：
  名称：

  Total synthesis of spatane diterpenes: the tricyclic nucleus

  摘要：

  A convergent, stereocontrolled construction of the cis,anti,cis-tricyclo[5.3.0.0(2,6)]decane nucleus of spatane diterpenes was achieved by 2-pi + 2-pi photocycloaddition of 2-cyclopenten-1-one, as an A-ring precursor, with a carbonyl-masked derivative of 6-methylbicyclo[2.2.1]hept-5-en-2-one as a temporarily bridged C-ring precursor. By design, the temporary bridge assures the correct stereochemical relationship between the B-ring stereocenters and the C-ring hydroxyl substituent that is present in latent form in the oxoethano bridge. Serendipitously, the bridge also fosters a favorable orientation of the photocycloaddition that contrasts with the nonselective 2-pi + 2-pi-photocycloadditions of unbridged 1-methylcyclopentenes with 2-cyclopenten-1-one. Wittig methylenation of the A-ring carbonyl in photoproduct 24 followed by hydrolysis to 25 and catalytic hydrogenation introduces a methyl group at position 1 with a 10:1 preference for the requisite stereochemistry in 26. Even higher stereoselectivity was achieved by SO2-promoted isomerization of the exocyclic C=C bond in 25 to an endocyclic disposition in 29 prior to catalytic hydrogenation. Johnson's sulfoximine method is especially effective for resolution of ketone 29. The oxoethano bridge in ketone 26n is oxidized rapidly but nonregioselectively by an H2SO4-catalyzed reaction with peracetic acid, producing a 57:43 mixture of 14 and 34. Regioselective generation of the desired lactone 14 could be accomplished by a much slower oxidation with peracetic acid and no added H2SO4. The necessary configuration at position 7 in 49 was generated stereoselectively by a novel homoallylic hydroxyl-directed, pseudointramolecular delivery of hydride to the methylenemalonic ester in the precursor 48. Conversion of the malonic ester moiety in 49 into an allylic alcohol was accomplished in 92% overall yield by monosaponification, decarboxylative condensation with formaldehyde and reduction of the resulting acrylic ester with i-Bu2AlH. Selective oxidation of the allylic hydroxyl followed by acetylation delivered acetate (+)-11a, which is identical with an oxidative degradation product from spatane diterpenes.

  DOI：

  10.1021/ja00008a043