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Communication | Special issue | Vol 59, No. 2, 2003, pp.501-504
Published online, 1st January, 1970
DOI: 10.3987/COM-02-S75
Hetero Diels-Alder Reaction Catalyzed by New Axially Dissymmetric Ligands with Fluorinated Chiral Centers

Masaaki Omote, Tomokuni Hasegawa, Kazuyuki Sato, Akira Ando, and Itsumaro Kumadaki*

*Faculty of Pharmaceutical Sciences, Setsunan University, 45-1, Nagaotoge-cho, Hirakata-shi, Osaka 573-0101, Japan

Abstract

We have reported a new type of axially dissymmetric ligand, (R)-bis{(R)-2,2,2-trifluorohydroxyethyl}biphenyl ((R)-(R)2-1), which showed an excellent asymmetric induction in the reaction of Et2Zn to benzaldehyde. Now, a pentafluoroethyl analog of this ligand ((R)-(R)2-6) was synthesized. Both ligands were found to work as a ligand for an asymmetric hetero Diels-Alder reaction of benzaldehyde (2) with the Danishefsky's diene (4). Titanium or aluminum complexes of (R)-(R)2-1 or (R)-(R)2-6 catalyzed this asymmetric reaction moderately to give products of up to 54% ee.