C2-Symmetric tetrafluorobenzobarrelenes as highly efficient ligands for the iridium-catalyzed asymmetric annulation of 1,3-dienes with 2-formylphenylboron reagents

New C-2-symmetric chiral diene ligands bearing a tetraflurobenzobarrelene framework were prepared via a [4+2] cycloaddition of 1,4-bis((methoxymethoxy)methyl)benzene with tetrafluorobenzyne. The diene ligands realized the iridium-catalyzed enantioselective [3+2] annulation of 1,3-dienes with 2-formylphenylboron reagents giving 1-indanol derivatives in high yields and with high enantioselectivities. (C) 2008 Elsevier Ltd. All rights reserved.