Chiral metal complexes. 28. A stereoselective synthesis of proline

Ewan F. Birse, Peter A. Williams*, Robert S. Vagg

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The complex Λ-β2-[Co(R,R-picchxn)(dehydropro)]2+, where R,R-picchxn is N,N′-di(2-picolyl)-1R, 2R-diaminocyclohexane and dehydropro is the anion of 1,2-dehydroproline may be synthesised quantitatively from Λ-β-[Co(R,R-picchxn)Cl2]+ and 5-amino-2-oxopentanoic acid in aqueous solution at room temperature. This ternary complex may in turn be reduced to Λ-β2-[Co(R,R-picchxn)(R,S-pro)]2+ (where pro is the anion of proline) in high yield by the use of aqueous sodium borohydride (also at room temperature) and the diastereoisomeric products separated quantitatively using chromatographic techniques. At 298.2 K the ratio of R-proline:S-proline produced is equal to 84:16 ± 2. Using the method, it is possible to stereoselectively synthesise 4- and 5- substituted diastereoisomers based on proline, in general.

Original languageEnglish
Pages (from-to)57-61
Number of pages5
JournalInorganica Chimica Acta
Volume148
Issue number1
DOIs
Publication statusPublished - 1 Aug 1988

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