Reinvestigation of the alkylation of pyroglutamate ester urethanes

被引：23

作者：

Charrier, JD ^{[1
]}

Duffy, JES ^{[1
]}

Hitchcock, PB ^{[1
]}

Young, DW ^{[1
]}

机构：

[1] Univ Sussex, CPES, Sussex Ctr Biomol Design & Drug Dev, Brighton BN1 9QJ, E Sussex, England

来源：

TETRAHEDRON LETTERS | 1998年 / 39卷 / 15期

基金：

英国生物技术与生命科学研究理事会; 英国工程与自然科学研究理事会;

关键词：

D O I：

10.1016/S0040-4039(98)00174-9

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Previous studies by several groups on the alkylation of pyroglutamic acid derivatives have led to a consensus that the stereoselectivity of alkylation at C-4 is invariably trans to the ester group at C-2. We have now discovered that this generalisation is not invariably correct and that, although for S(N)1-type electrophiles stereoselectivity is in fact trans, S(N)2-type electrophiles can give the thermodynamically less stable cis products with high diastereoselectivity. Use of the bulky proton source 2,6-di-tert-butylphenol to quench these reactions yields cis isomers as the only products in good yield thus making direct alkylation of pyroglutamic add derivatives a useful starting point for the synthesis of homochiral target compounds. (C) 1998 Elsevier Science Ltd. All rights reserved.

引用

页码：2199 / 2202

页数：4

共 18 条

[1] STEREOSELECTIVE METHYLATIONS OF BICYCLIC LACTAMS DERIVED FROM PYROGLUTAMIC ACID [J].

ARMSTRONG, RW ;

DEMATTEI, JA .

TETRAHEDRON LETTERS, 1991, 32 (41) :5749-5752

[2] STEREOSPECIFIC SYNTHESIS OF (2S,4R)-[5,5,5-H-2(3)]-LEUCINE [J].

AUGUST, RA ;

KHAN, JA ;

MOODY, CM ;

YOUNG, DW .

TETRAHEDRON LETTERS, 1992, 33 (32) :4617-4620

[3] Stereospecific synthesis of (2S,4R)-[5,5,5-H-2(3)]leucine [J].

August, RA ;

Khan, JA ;

Moody, CM ;

Young, DW .

JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1, 1996, (06) :507-514

[4] AMINO-ACID SYNTHESIS USING (L)-PYROGLUTAMIC ACID AS A CHIRAL STARTING MATERIAL [J].

BALDWIN, JE ;

MIRANDA, T ;

MOLONEY, M ;

HOKELEK, T .

TETRAHEDRON, 1989, 45 (23) :7459-7468

[5] ASYMMETRIC SYNTHESES OF BETA-PHENYLALANINE, ALPHA-METHYL-BETA-PHENYLALANINES AND DERIVATIVES [J].

DAVIES, SG ;

GARRIDO, NM ;

ICHIHARA, O ;

WALTERS, IAS .

JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1993, (14) :1153-1155

[6] STEREOSELECTIVE REACTIONS OF LITHIUM ENOLATES DERIVED FROM N-BOC PROTECTED PYROGLUTAMIC ESTERS [J].

EZQUERRA, J ;

PEDREGAL, C ;

RUBIO, A ;

YRURETAGOYENA, B ;

ESCRIBANO, A ;

SANCHEZFERRANDO, F .

TETRAHEDRON, 1993, 49 (38) :8665-8678

[7] F-19 nuclear magnetic resonance chemical shifts of fluorine containing aliphatic amino acids in proteins: Studies on Lactobacillus casei dihydrofolate reductase containing (2S,4S)-5-fluoroleucine [J].

Feeney, J ;

McCormick, JE ;

Bauer, CJ ;

Birdsall, B ;

Moody, CM ;

Starkmann, BA ;

Young, DW ;

Francis, P ;

Havlin, RH ;

Arnold, WD ;

Oldfield, E .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (36) :8700-8706

[8] The synthesis of enantiopure omega-methanoprolines and omega-methanopipecolic acids by a novel cyclopropanation reaction: The ''flattening'' of proline [J].

Hanessian, S ;

Reinhold, U ;

Gentile, G .

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH, 1997, 36 (17) :1881-1884

[9] SYNTHESIS OF (2S,4S) 2-CARBOXY-4-PYRROLIDINE ACETIC-ACID, A CONFORMATIONALLY CONSTRAINED 2-AMINO ADIPIC ACID ANALOG [J].

LANGLOIS, N ;

ROJAS, A .

TETRAHEDRON LETTERS, 1993, 34 (15) :2477-2480

[10] ON THE INTERACTION BETWEEN LITHIUM ENOLATES AND SECONDARY-AMINES IN SOLUTION AND IN THE CRYSTAL [J].

LAUBE, T ;

DUNITZ, JD ;

SEEBACH, D .

HELVETICA CHIMICA ACTA, 1985, 68 (05) :1373-1393

← 1 2 →