Enantioselective reduction of ketones with triethoxysilane catalyzed by chiral bis-oxazoline titanium complexes

Chemical Communications

Volumn , Issue 1, 1999, Pages 39-40

  Bandini, Marco ^a   Cozzi, Pier Giorgio ^a   Negro, Lucia ^a   Umani Ronchi, Achille ^a  

^a UNIVERSITY OF BOLOGNA   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

KETONE; LITHIUM DERIVATIVE; OXAZOLINE DERIVATIVE; SILANE DERIVATIVE; TITANIUM; TRIETHOXYSILANE; UNCLASSIFIED DRUG;

ARTICLE; CATALYSIS; CHEMICAL STRUCTURE; REDUCTION;

EID: 0033531137     PISSN: 13597345     EISSN: None     Source Type: Journal    
DOI: 10.1039/a807028h     Document Type: Article

References (24)

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9. (b) X. Verdaguer, U. E. W. Lange, M. T. Reding and S. L. Buchwald, J. Am. Chem. Soc., 1996, 118, 6784; X. Verdaguer, U. E. W. Lange and S. L. Buchwald, Angew. Chem., 1998, 110, 1174; Angew. Chem., Int. Ed., 1998, 37, 1103. For the use of other chiral ansa-titanocenes see also: S. Xin and J. F. Harrod, Can. J. Chem., 1995, 73, 999; R. L. Halterman, T. M. Ramsey and Z. Chen, J. Org. Chem., 1994, 59, 2642.
10. (b) X. Verdaguer, U. E. W. Lange, M. T. Reding and S. L. Buchwald, J. Am. Chem. Soc., 1996, 118, 6784; X. Verdaguer, U. E. W. Lange and S. L. Buchwald, Angew. Chem., 1998, 110, 1174; Angew. Chem., Int. Ed., 1998, 37, 1103. For the use of other chiral ansa-titanocenes see also: S. Xin and J. F. Harrod, Can. J. Chem., 1995, 73, 999; R. L. Halterman, T. M. Ramsey and Z. Chen, J. Org. Chem., 1994, 59, 2642.
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19. In these cases, only racemic alcohol was obtained. Reduction of titanium depending on the ligand is well known problem in metallocene chemistry.
20. Aliphatic, non-branched aromatic and cyclic ketones were reduced with our titanium catalyst in lower ees. For example, the reduction of octan-2-one and indan-2-one afforded the corresponding alcohols in 65% yield, 20% ee and 70% yield, 29% ee, respectively.
21. D values reported in the literature. The absolute configurations of 10b and the other halo ketones were assigned by analogy.
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