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Hiroshige Koide, Motokazu Uemura and Motokazu Uemura
Abstract
Axially chiral N,N-diethyl 2,6-disubstituted benzamides are prepared stereoselectively in an optically active form from a planar chiral (arene)chromium complex.
References
J. H. Ackerman and G. M. Laidlaw, Tetrahedron Lett., 1969, 4487 CrossRefCAS; 1970,
2381; P. M. van Lier, G. H. W. M. Meulendijks and H. M. Buck, Rec. Trav. Chim. Pays-Bas, 1983, 102, 337 Search PubMed; M. A. Cuyegkeng and A. Mannschreck, Chem. Ber., 1987, 120, 803 CAS; L. A. M. Bastiaansen, J. A. Kanters, F. H. van der Steen, J. A. C. de Graaf and H. M. Buck, J. Chem. Soc., Chem. Commun., 1986, 536 CrossRefCAS; C. Roussel and U. Berg, Adv. Heterocycl. Chem., 1988, 43, 173 RSC.
M. A. Cuyegkeng and A. Mannschreck, Chem. Ber., 1987, 120, 803 CrossRefCAS; W. H. Pirkle, C. J. Welch and A. J. Zych, J. Chromatogr., 1993, 648, 101 CrossRefCAS.
P. Bowles, J. Clayden and M. Tomkinson, Tetrahedron Lett., 1995, 36, 9219 CrossRefCAS; J. Clayden, N. Westlund and F. X. Wilson, Tetrahedron Lett., 1996, 37, 5577 CrossRefCAS; J. Clayden and J. H. Pink, Tetrahedron Lett., 1997, 38, 2565 CrossRefCAS; J. Clayden, M. Darbyshire, J. H. Pink, N. Westlund and F. X. Wilson, Tetrahedron Lett., 1997, 38, 8587 CrossRefCAS; J. Clayden, J. H. Pink and S. A. Yasin, Tetrahedron Lett., 1998, 39, 105 CrossRefCAS.
S. Thayumanavan, P. Beak and D. P. Curran, Tetrahedron Lett., 1996, 37, 2899 CrossRefCAS.
Enantiomerically pure compound was obtained by optical resolution of diastereomers obtained from L-valinol; see S. G. Davies and C. L. Goodfellow, J. Chem. Soc., Perkin Trans. 1, 1990, 393 Search PubMed.
V. Snieckus, Chem. Rev., 1990, 90, 879 CrossRefCAS.
First symbol S indicates the configuration of the tricarbonylchrom ium - complexed
arene carbon substituted by the diethylamido group, the second S shows the axial
chirality.
The optical purities of axial chiral benzamides were determined by 1H
NMR spectroscopy in the presence of chiral shift reagent, Eu(tfc)3.
The optical purity of compound 5 decreased with time of standing at
room temperature; 86% ee after 6 h, 70% ee after
24 h.
M. Uemura, K. Kobayashi, K. Isobe, T. Minami and Y. Hayashi, J. Org. Chem., 1986, 51, 2859 CrossRefCAS.
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