Collect. Czech. Chem. Commun.
2004, 69, 1517-1536
https://doi.org/10.1135/cccc20041517
Novel Route to Enantiopure 2,2'-Diaryl-1,1'-binaphthalenes by Stereoconservative Suzuki Arylation at Positions 2 and 2'
Henrich Brath, Margaréta Dubovská, Michal Juríček, Peter Kasák and Martin Putala*
Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-2, 842 15 Bratislava, Slovak Republic
Abstract
The Suzuki arylation of enantiopure 2,2'-diiodo-1,1'-binaphthalene affords the 2,2'-diarylated products in considerable yields (up to 52%), however, significantly racemized. The reversed-polarity approach, using novel enantiopure 1,1'-binaphthalene-2,2'-diyldiboronic acid, prepared either by resolution or by stereoconservative boronation, allowed, after optimization of coupling conditions, to obtain the model 2,2'-ditolylated product in good yield (56%) as well, but in addition, without impairing of enantiomeric purity (i.e. stereoconservatively). The developed synthetic approach was found to be an expedient method for the synthesis of enantiopure 2,2'-diaryl-1,1'-binaphthalenes, especially for those with electron-neutral and electron-deficient poor aryl groups. Observing that the diboronic acid decomposes by hydrodeboronation under the reaction conditions, 2-aryl-1,1'-binaphthalenes were isolated as the main products from the reaction with less reactive electron-rich aryl iodides.
Keywords: Biaryls; Binapthyls; Boronic acids; C–C coupling; C2-Symmetry; Palladium; Steric hindrance; Cross-coupling reactions; Stereoselective synthesis.
References: 29 live references.
