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Synfacts 2007(1): 0092-0092  
DOI: 10.1055/s-2006-955660
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Highly Enantioselective Synthesis of 1,4-Benzoxazinones and α-Amino Acids

Contributor(s): Benjamin List, Daniela Kampen
J. Wolfer, T. Bekele, C. J. Abraham, C. Dogo-Isonagie, T. Lectka*
Johns Hopkins University, Baltimore, USA
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Publication History

Publication Date:
15 December 2006 (online)

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Significance

An organocatalytic asymmetric [4+2] cycloaddition has been developed. Ketene enolates, generated in situ from acid chlorides 1 and 10 mol% of chiral cinchona alkaloid 3, react with o-benzoquinone imides 2 to give 1,4-benz­oxazinones 4 in moderate yields and excellent enantioselectivities. Cycloadducts 4 can be transformed in situ to the corresponding acyclic α-amino acid derivatives 5 via nucleophilic addition of both alcohols and amines in good yields and with preservation of the stereochemistry.