(+/-)-(1RS,3SR,4SR,7SR)-7-Bromo-5-oxo-2-oxabicyclo<2.2.1>hept-3-yl Acetate | 131635-63-7

• 分子结构分类: 有机化合物 - 有机杂环化合物
• 英文名称: (+/-)-(1RS,3SR,4SR,7SR)-7-Bromo-5-oxo-2-oxabicyclo<2.2.1>hept-3-yl Acetate
• CAS: 131635-63-7
• 化学式: C₈H₉BrO₄
• 分子量: 249.061
• InChiKey: MTFCAIREOOZAKP-SZVWITLZSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.63
• 重原子数：
  13.0
• 可旋转键数：
  1.0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.75
• 拓扑面积：
  52.6
• 氢给体数：
  0.0
• 氢受体数：
  4.0

反应信息

• 作为产物：
  描述：

  乙酸酐 、 7-oxabicyclo[2.2.1]hept-5-en-2-one 在 溴 作用下， 反应 0.08h， 以34%的产率得到(+/-)-(1RS,3SR,4SR,7SR)-7-Bromo-5-oxo-2-oxabicyclo<2.2.1>hept-3-yl Acetate
  参考文献：
  名称：

  Total, asymmetric synthesis of (+)-castanospermine, (+)-6-deoxycastanospermine, and (+)-6-deoxy-6-fluorocastanospermine

  摘要：

  Bromination of the dibenzyl acetal of (-)-(1S,4S)-7-oxabicyclo[2.2.1]hept-5-en-2-one ((-)-5) led to (+)-(1S,5S,6S,7S)-6-endo-(benzyloxy)-5-exo-bromo-7-oxabicyclo[2.2.1]heptan-2-one (25). Baeyer-Villiger oxidation of 25 gave 2-O-benzyl-3-bromo-3,5-dideoxy-beta-L-arabino-hexofuranosidurono-6,1-lactone (26). Methanolysis of 26 afforded the corresponding methyl (methyl alpha-beta-L-arabinofuranosid)uronates (27 + 28). The alpha anomer 27 was reduced with DIBAH into methyl 2-O-benzyl-3-bromo-3,5-dideoxy-beta-L-arabino-hexofuranoside (29). Mesylation of the primary alcohol, followed by treatment with NH3 gave methyl 2-O-benzyl-3,5-6-trideoxy-3,6-imino-beta-L-lyxo-hexofuranoside (32). Acetylation of the amine with ClCH2COCl, acetolysis of the methyl furanoside followed by Arbuzov condensation with (EtO)3P, and then intramolecular Horner-Emmons reaction led to (5S,6S,7S)-7-hydroxy-5-(benzyloxy)-1-azabicyclo[4.3.0]non-3-en-2-one (37). Base-catalyzed hydrolysis of the corresponding epoxide 43 ((1S,6S,7S,8R,8aS)-8-(benzyloxy)-6,7-epoxy-1-hydroxyoctahydroindolizidin-5-one) followed by reduction of the lactam and deprotection of the alcoholic functions afforded (+)-castanospermine ((+)-1). The conversion of (-)-5 into (+)-1 was highly stereoselective, requiring the isolation of 10 synthetic intermediates and with an overall yield of 15.2%. Reduction of 43 with BH3.Me2S or its treatment with HF.Et3N allowed one to prepare readily (+)-6-deoxycastanospermine ((+)-2 and 6-deoxy-6-fluorocastanospermine ((+)-3). The crystal structure of (+)-3 is also reported.

  DOI：

  10.1021/jo00006a031