Synthesis of axially chiral 1,1′-binaphthalenes by palladium-catalyzed cross-coupling reactions of triorganoindium reagents.

Mosquera, A.; Pena, M. A.; Pérez Sestelo, J.; Sarandeses, L. A.


Eur. J. Org. Chem. 2013, 2555–2562 (DOI: 10.1002/ejoc.201300042).

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1,1’-Binaphthalenes and heterocyclic analogues can be efficiently prepared by palladium-catalysed cross-coupling reactions between tri(1-naphthyl)indium reagents and 1-halonaphthalenes and haloisoquinolines. The reactions were usually carried out in THF at 80 °C with a slight excess of the indium reagent (40 mol-%) and a low catalyst loading (4 mol% Pd) to afford the cross-coupling products in good yields (45–99%). The method allows the synthesis of sterically hindered 2-substituted and 2,2’-disubstituted 1,1’-binaphthalenes and naphthylisoquinolines. In addition, the coupling reactions can be performed enantioselectively and the best enantiomeric excesses were obtained by using the chiral amino-phosphane ferrocenyl ligand (R,S)-PPFA.