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Chiral squaramide derivatives are excellent hydrogen bond donor catalysts.

ABSTRACT: Thioureas represent the dominant platform for hydrogen bond promoted asymmetric catalysts. A large number of reactions, reported in scores of publications, have been successfully promoted by chiral thioureas. The present paper reports the use of squaramides as a highly effective new scaffold for the development of chiral hydrogen bond donor catalysts. Squaramide catalysts are very simple to prepare. The (-)-cinchonine modified squaramide (5), easily prepared through a two-step process from methyl squarate, was shown to be an effective catalyst, even at catalyst loadings as low as 0.1 mol%, for the conjugate addition reactions of 1,3-dicarbonyl compounds to beta-nitrostyrenes. The addition products were obtained in high yields and excellent enantioselectivities.

SUBMITTER: Malerich JP

PROVIDER: S-EPMC2701638 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature

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Chiral squaramide derivatives are excellent hydrogen bond donor catalysts.

Malerich Jeremiah P JP Hagihara Koji K Rawal Viresh H VH

Journal of the American Chemical Society 20081011 44

Thioureas represent the dominant platform for hydrogen bond promoted asymmetric catalysts. A large number of reactions, reported in scores of publications, have been successfully promoted by chiral thioureas. The present paper reports the use of squaramides as a highly effective new scaffold for the development of chiral hydrogen bond donor catalysts. Squaramide catalysts are very simple to prepare. The (-)-cinchonine modified squaramide (5), easily prepared through a two-step process from methy ...[more]

PMID: 18847268

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