3,4-二羟基-2,5-双-[2-′(4′-取代唑啉)]呋喃的合成及其应用

Synthesis and Application of 3,4-Dihydroxy-2,5-bis(2′-(4′-substitutedoxazolinyl))furan

以3,4-二羟基-2,5-呋喃二甲酸或其二甲酯为原料,与手性氨基醇直接缩合,经一步反应合成了3个3,4-二羟基-2,5-双-[2′-(4-′-取代(口恶)唑啉)]呋喃化合物,产率为90%～94%,其结构经1 H NMR谱、IR谱、MS谱和元素分析测试技术得到确证;并应用这些手性双(口恶)唑啉配体,初步探讨了β-萘乙酮在KBH4或NaBH4作用下的不对称还原反应. 结果表明,以环己烷作溶剂,采用n(配体): n(还原剂): n(β-萘乙酮)=0.04:1.6:1在0 ℃下反应72 h,产物的ee值高达83.2%,且(口恶)唑啉环上4位取代基为苄基的呋喃类双(口恶)唑啉,其对映选择性优于取代基为乙基的同类配体.

Three 3,4-dihydroxy-2,5-bis （2＇-（4＇-substitutedoxazolinyl） ） furans were synthesized in yields of 90% -94% from 3,4-dihydroxy-2,5-furan diearboxylie acid or its dimethyl ester with ehiral β -amino alcohol via a one-step reaction, and their chemical structures were determined by ^1H NMR, IR, MS, and elemental analysis. With these ehiral bisoxazoline ligands, the asymmetric reduction of β-aeetonaphthalene by KBH4 or NaBH4 was preliminarily studied. The enantiomerie excess of the reduction product was up to 83.2% using eyelohexane as the solvent, n（ligand） ： n（ reduetive agent） ： n（β-aeetonaphthalene ） = 0.04： 1.6： 1, and 72 h reaction time at 0℃, and furan-eontaining bisoxazoline with 4-benzyl on oxazoline rings exhibited higher enantioseleetivity than congeneric bisoxazolines with 4-ethyl on oxazoline rings.