Julia-colonna不对称环氧化反应

  • A+

在手性聚α-氨基酸催化下,缺电子烯烃在氧化剂(过氧化氢或过氧化脲)氧化下得到单一构型的环氧化物的反应。此反应通常在碱性条件下进行。


反应机理

反应属于亲核环氧化,底物中没有吸电子基团的话反应不能进行。


反应实例

Catalyst (1).  To a solution of N-carboxy-L-alanine anhydride (2.5 g, 21.7 mmol) in anh MeCN (50 mL) was added MeCN (20 mL with 0.43 mmol H2O). After 4 days stirring at 20 C the solvent was removed in vacuum and the residue stirred for 24 h in Et2O, filtered and dried.

Epoxide (3). To a solution of chalcone 2 (500 mg, 2.4 mmol) in PhMe (6 mL) was added 1 (400 mg) and then the mixture was stirred for 30 min at 20 C. The mixture was added to a solution of NaOH in H2O2 (0.08 g/mL, 4.4 mL) and stirred for 24 h. The reaction was monitored by TLC (silica gel, PE:Et2O 9:1). Usual workup and chromatography afforded 494 mg of 3 (92%, 96% ee).

【Julia S, Colonna S, Tetrahedron, 1984, 40, 5207】



Epoxide (5). To I-PLL(immobilized poly-L-leucine, 7 g) in THF (50 mL) were added DBU (4.1 mL, 27.48 mmol) and UHP (Urea hydrogen peroxide)

 (2.07 g, 21.98 mmol). Under stirring was added 4 (4.01 g, 18.37 mmol), followed after 3 h by a second quantity of DBU and UHP. Separation of the epoxide  3.20 g of 5 (70% yield from 4), mp 53–55 C, 96% ee.

【Roberts SM, J Chem Soc Perkin 1, 1997, 3501】



相关文献

1 Julia S, Colonna S Angew Chem Int 1980 19 929

2 Julia S, Colonna S J Chem Soc Perkin 1 1982 1317

3 Julia S, Colonna S Tetrahedron 1983 39 1655

4 Julia S, Colonna S Tetrahedron 1984 40 5207

5 Roberts SM J Chem Soc Perkin 1 1997 3501

6 Geller T J Chem Soc Perkin 1 1999 1397

7 Jayaprakash D J Mol Catal A Chem 2003 196 145

8 Shibasaki M Chem Asian J 2007 2 257

9 Shing TKM Tet Asymm 2009 20 883



编译自:Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 239-240.


相关反应

亲核环氧化反应(Nucleophilic Epoxidation with Peroxide)

Jacobsen–Katsuki环氧化反应

史氏不对称环氧化反应

Sharpless不对称环氧化反应

Prilezhaev氧化反应


weinxin
我的微信
关注我了解更多内容

发表评论

目前评论:0