Abstract
l-Proline derived diastereoisomeric [4.4]-spirolactams have been prepared by a reductive-amination reaction of (R)- or (S)-alanine methyl ester, followed by thermal cyclisation of the resulting amine onto the proline ester group in refluxing toluene. Under similar conditions (R)- or (S)-phenylalanine methyl ester gave no cyclisation products, while R- or S-α-methylbenzylamine required treatment with NaNH2 in refluxing toluene to induce cyclisation giving diastereoisomeric [4.4]-spirolactams.
Original language | English |
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Pages (from-to) | 5247-5250 |
Number of pages | 4 |
Journal | Tetrahedron Letters |
Volume | 47 |
Issue number | 30 |
DOIs | |
Publication status | Published - 24 Jul 2006 |