Phase-transfer-catalyzed asymmetric acylimidazole alkylation

被引：26

作者：

Andrus, Merritt B. ^{[1
]}

Christiansen, Michael A. ^{[1
]}

Hicken, Erik J. ^{[1
]}

Gainer, Morgan J. ^{[1
]}

Bedke, D. Karl ^{[1
]}

Harper, Kaid C. ^{[1
]}

Mikkelson, Shawn R. ^{[1
]}

Dodson, Daniel S. ^{[1
]}

Harris, David T. ^{[1
]}

机构：

[1] Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA

来源：

ORGANIC LETTERS | 2007年 / 9卷 / 23期

关键词：

D O I：

10.1021/ol702197r

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

2-Acylimidazoles are alkylated under phase-transfer conditions with cinchonidinium catalysts at -40 degrees C with allyl and benzyl electrophiles in high yield with excellent enantioselectivity (79 to >99% ee). The acylimidazole substrates are made in three steps from bromoacetic acid via the N-acylmorpholine adduct. The catalyst is made in high purity allowing for S-product formation (6-20 h) under mild conditions, consistent with an ion-pair mechanism. The products are readily converted to useful ester products using methyltriflate and sodium methoxide, via a climethylacylimidazolium intermediate without racemization. The process is efficient, direct, and amenable to other electrophiles and transformations that proceed through an enolate intermediate.

引用

页码：4865 / 4868

页数：4

共 21 条

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