Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2006-12-29
2010-08-03
Saeed, Kamal A (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
07767825
ABSTRACT:
The present invention relates to a method for preparing 2,2′,6,6′-tetraoxazolinyl biphenyl ligand in chemical industry field. In the present invention, compound (III) is reacted with an activator that can activate the hydroxyl group selected from the group consisting of alkyl halosulfonium compound, aryl halosulfonium compound, phosphoryl chloride, phosphorus pentachloride, thionyl chloride and triphenyl phosphine, in the presence of alkali(s), to give the target product (IV), 2,2′,6,6′-tetraoxazolinyl biphenyl ligand. The ligand of the present invention can be used in various asymmetric reactions catalyzed by metals, with high reactivity and stereoselectivity, and thus represents a good application outlook. The 2,2′,6,6′-tetraoxazolinyl biphenyl ligand has the formula of:wherein, R1=hydrogen, alkyl, substituted or unsubstituted aryl, substituted or unsubstituted benzyl; R2=hydrogen, alkyl, substituted or unsubstituted aryl, substituted or unsubstituted benzyl; R3=hydrogen, alkyl, substituted or unsubstituted aryl, substituted or unsubstituted benzyl; R4=hydrogen, alkyl, substituted or unsubstituted aryl, substituted or unsubstituted benzyl.
REFERENCES:
Moorlag et al, “As Asymmetric Synthesis of a C2Symmetric Tetrasubstituted Biaryl: 2,2′-Dihydroxy-6,6′-Dimethyl-1,1′-Biphenyl, A Stable Chiral System,” Tetrahedron Letters, vol. 34, No. 44, pp. 6993-6996, 1993.
Andrus et al., “Efficient Synthesis of 1,1′-Binaphthyl and 2,2′-Bi-o-tolyl-2,2′-bis(oxazoline)s and Preliminary Use of the Catalytic Asymmetric Allylic Oxidation of Cyclohexene,” Journal of Organic Chemistry, vol. 62, No. 26, pp. 9365-9368, 1997.
Gant T.G. et al, “The First Enantioselective Synthesis of the Chemotactic Factor Sirenin by an Intramolecular [2+1] Cyclization Using a New Chiral Catalyst”, Tetrahedron Letters, vol. 36, No. 48, pp. 8745-8748 (1995).
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Qlao Z. et al., “Progress of Chiral Bis(oxazoline)-Metal Complexes Utilized in Asymmetric Cyclopropanation”, Chinese Journal of Organic Chemistry, vol. 24, No. 1, pp. 15-22 (2004).
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U.S. Appl. No. 12/159,440 to Wanbin Zhang et al., filed Jun. 27, 2008.
Wang Feijun
Zhang Wanbin
Zhang Yongjian
Bianchi Kristin
Greenblum & Bernstein P.L.C.
Saeed Kamal A
Shanghai Jiaotong University
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