New Route to Synthesize Enantiopure 6-Methyl and 6-Ethyl Bicyclic Lactams Derived from (R)-(-)-2-Phenylglycinol
Ana M. Lumbreras,1 Dino Gnecco,*1 Joel L. Terán,1 Jorge Juárez,1 Ma. Laura Orea,1 Raúl G. Enríquez2 and Simón Hernández2
1 Centro de Química. Instituto de Ciencias. Benemérita Universidad Autónoma de Puebla. Lab. Síntesis Orgánica. Edificio 194. Complejo de Ciencias, Ciudad Universitaria. C.P. 72570 Puebla, Pue. México. *dgnecco@siu.buap.mx.
2 Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, D.F. 04510.
]]> Recibido el 25 de enero de 2007
Abstract
The diastereoselective synthesis of bicyclic lactams (-)-(3R,6S,8aS)-6-methyl- and -6-ethyl-3-phenyl-hexahydrooxazolo[3,2-a]pyridin-5-ones 4(a-b) and (-)-(3R,6R,8aS)-6-methyl-3-phenyl-hexahydrooxazolo[3,2-a]pyridin-5-one 4'a are described.
Keywords: Enantiopure bicyclic lactams.
Resumen
Se describe la síntesis diasteroselectiva de las biciclo lactamas (-)-(3R,6S,8aS)-6-metil- y -6-etil-3-fenil-hexahidrooxazolo[3,2-a]piridin-5-onas 4(a-b), y la (-)-(3R,6R,8aS)-6-metil-3-fenil-hexahidrooxazol[3,2-a]piridin-5-ona 4'a.
Palabras clave: Biciclo lactamas enantiopuras.
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Acknowledgements
We are grateful to CONACyT for financial support project 46930. AML thanks CONACyT for doctoral scholarship (171984).
References
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4. The so different diastereomeric ratios observed for epimeric mixtures 2a (60:40) and 2b (90:10) could be associated the size of the substituent at C-3.
5. Terán, J. L.; Gnecco, D.; Galindo, A.; Juárez, J.; Bernès, S.; Enríquez, R. Tetrahedron-Asymmetry 2001, 12, 357-360. [ Links ]
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7. Crystallographic data of 4'a have been deposited with the Cambridge Crystallographic Data Centre CCDC 618864. Copies of the data can be obtained, free charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK e-mail: deposit@ccdc.cam.ac.uk
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