New Palladium(II)‐Catalyzed Asymmetric 1,2‐Dibromo Synthesis.

Abstract

Enantioselective synthesesEnantioselective syntheses O 0031 New Palladium(II)-Catalyzed Asymmetric 1,2-Dibromo Synthesis. -The oxidation of olefins by chiral monometallic or bimetallic Pd(II)-Cu(II) catalysts in bromide-containing aqueous THF solutions affords chiral 1,2-dibromides. With α-olefins (I), the enantioselectivities are about 95% while internal alkenes (III) give lower enantioselectivities [around 80% e.e. from (IIIa) and (IIIb), 34% e.e. from (IIIc)]. -(EL-QISAIRI, A. K.; QASEER, H. A.; KATSIGRAS, G.; LORENZI, P.; TRIVEDI, U.; TRACZ, S.; HARTMAN, A.; MILLER, J. A.; HENRY*, P. M.; Org. Lett. 5 (2003) 4, 439-441; Dep. Chem., Loyola Univ., Chicago, IL 60626, USA; Eng.) -Klein 25-030