An asymmetric synthesis of α-amino acid derivatives from racemic ethyl N-phenylsulphonyl-α-bromoglycinate using homochiral aluminium complexes

Tetrahedron Letters

Volumn 37, Issue 27, 1996, Pages 4795-4796

  Morgan, Paul E ^a   Whiting, Andrew ^a   McCague, Ray ^b  

^a UNIVERSITY OF MANCHESTER   (United Kingdom)

^b Chiroscience Ltd   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

AMINO ACID DERIVATIVE;

ARTICLE; DRUG SYNTHESIS; REACTION ANALYSIS; TECHNIQUE;

EID: 0030200490     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00938-0     Document Type: Article

References (12)

1. 1. a) Harada, K.; Okawara, T.; J. Org. Chem., 1973, 38, 707;
2. b) Stout, D.M.; Black, L.A.; Matier, W.L.; ibid, 1983, 48, 5369;
3. c) For a recent review see Duthaler, R.O.; Tetrahdron, 1994, 50, 1539.
4. 2. a) McFarlane, A.K.; Thomas, G.; Whiting, A.; Tetrahedron Lett., 1993, 34, 2379;
5. b) idem, J. Chem. Soc., PerkinTrans. I, 1995, 2803.
6. 3. Maggin, M; Prato, M.; Scorrano, G.; Tetrahedron Lett., 1990, 32, 6243
7. 4. Morgan, P.; Whiting, A.; unpublished results.
8. 5. Alanine analogue 3 (R=Me) was reduced with lithium aluminium hydride and converted into the (+)-Mosher ester.
9. 6. The absolute stereochemistry of 3 (R=Me) was determined by comparison of the (+)-Mosher ester derivative prepared in reference 5, with that prepared from commercial L-alanine.
10. 7. The absolute stereochemistry of 3 (R=Et) was determined by comparing the hplc retention times of the products from Table 1, with both racemic 3 (R=Et) and the N-phenylsulphonyl ethyl ester derivative of commercial (S)-(+)-2-aminobutyric acid.
11. 4) and evaporatated to yield the crude α-substituted product 3b as an off-white solid. Separation of the binaphthol (quantitative recovery) and 3b by silica gel chromatography gave pure 3b as a white solid (0.379 g, 90 %). Note: 3c was not purified by chromatography; binaphthol was removed by selective precipitation from ether-hexane.
12. 9. Williams, R.M.; Sinclair, P.J.; Zhai, D.; Chen, D.; J. Am. Chem. Soc., 1988, 110, 1547.