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Synthesis 1995; 1995(8): 1038-1050
DOI: 10.1055/s-1995-4042
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Chiral Aminal Templates: Diastereoselective Addition to Hydrazones; An Asymmetric Synthesis of α-Amino Aldehydes

Alex Alexakis* , Nathalie Lensen, Jean-Philippe Tranchier, Pierre Mangeney, J. Feneau-Dupont, J. P. Declercq
  • *Laboratoire de Chimie des Organoéléments, URA CNRS 473, Université P. et M. Curie, Tour 44-45 E2, 4 Place Jussieu, F-75252 Paris 05, France, Fax +33(1)44277150
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Publication Date:
31 December 2000 (online)

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The monohydrazone of glyoxal may be derivatized into a chiral aminal with diamine 7. The resulting chiral reagent 13 reacts with complete diastereocontrol with organolithium reagents in THF. This sterically controlled reaction may be altered to chelation control by using Grignard reagents in toluene, affording the opposite diastereomer in excellent de. The N-N bond of the hydrazine functionality is then cleaved with Raney nickel, assisted by ultrasound. After protection of the resulting primary amino functionality, the aminal is hydrolyzed to afford the desired α-amino aldehydes without epimerization. The same reaction sequence, without cleavage of the N-N bond, affords an α-hydrazino aldehyde.

glyoxal - chiral aminals - hydrazones - chiral α-amino aldehydes