Asymmetric conjugate addition of cis-2-arylethenylboronic acids catalyzed by chiral diene/rhodium complexes: 1,4-rhodium shift from alkenylrhodium to arylrhodium intermediates
摘要:
The reaction of (E)-1,2-diphenylethenylboronic acid 1 with 2-cyclohexenone in the presence of a chiral diene/rhodium catalyst (5 mol %) gave 3-[2-((E)-2-phenylethenyl)phenyl]cyclohexanone in 99% yield with 98.7% ee; the catalytic cycle involves a 1,4-rhodium shift from a 2-phenylethenylrhodium to an ortho-alkenylphenylrhodium intermediate. In the reaction of 1 with (E)-1-phenyl-2-buten-1-one, either the tandem 1,4-shift/arylation product or the direct alkenylation product is formed selectively by an appropriate choice of chiral diene ligand. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis of Trisubstituted Alkenes via Direct Oxidative Arene–Alkene Coupling
作者:Roderick C. Jones、Michał Gałęzowski、Donal F. O’Shea
DOI:10.1021/jo401326f
日期:2013.8.16
2-disubstituted alkene oxidative couplings, providing an efficient route to trisubstitutedalkenes. The acetonitrile cosolvent dramatically accelerates the rate of reaction, and an insoluble inorganic oxidant limits unwanted oxidation of substrates. The scope of this procedure is illustrated with arenes and alkenes containing electron-donating and -withdrawing substituents resulting in a general synthetic