Asymmetric Oxidative Cyclization of o-Phenolic Oxime-Esters: First Synthesis of Enantiomerically Enriched Spiroisoxazoline Methyl Esters.
Asymmetric Oxidative Cyclization of o-Phenolic Oxime-Esters: First Synthesis of Enantiomerically Enriched Spiroisoxazoline Methyl Esters.
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邻酚肟酯的不对称氧化环化：对映体富集的螺异恶唑啉甲酯的首次合成。
DOI：
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发表时间：
1997
影响因子：
3.6
通讯作者：
O. Hoshino
中科院分区：
文献类型：
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作者：
M. Murakata;M. Tamura;O. Hoshino
描述了一种合成对映体富集的环己二烯酮螺异恶唑啉 (-)-2a 的新方法。使用新型光学活性叔醇(-)-3作为手性助剂，邻酚肟酯1c的不对称分子内氧化环化反应顺利进行，得到环己二烯酮螺异恶唑啉2c，产率83%。以外消旋(1S,8R,9R,10R)-8-苯基-1-十氢化醇(4)为原料，通过光学拆分合成了具有光学活性的叔醇(-)-3。用CF(3)COOH除去2c中的手性助剂，然后甲基化，得到具有S构型的甲酯(-)-2a，74％ee(71％化学收率)。 2a的绝对构型是通过海洋天然产物(+)-航空硫素的合成来确定的。
A new method for the synthesis of enantiomerically enriched cyclohexadienone spiroisoxazoline (-)-2a has been described. Asymmetric intramolecular oxidative cyclization of the o-phenolic oxime-ester 1c using a novel optically active tertiary alcohol (-)-3 as a chiral auxiliary proceeded smoothly to afford cyclohexadienone spiroisoxazoline 2c in 83% yield. Opitcally active tertiary alcohol (-)-3 was synthesizied from racemic (1S,8R,9R,10R)-8-phenyl-1-decalol (4) by optical resolution. Removal of the chiral auxiliary in 2c with CF(3)COOH followed by methylation gave methyl ester (-)-2a in 74% ee (71% chemical yield) having S-configuration. The absolute configuration of 2awas determined by the synthesis of the marine natural product (+)-aerothionin.