Rh(I)/diene-catalyzed addition reactions of aryl/alkenylboronic acids with aldehydes

[Rh(COD)Cl]2-catalyzed addition reactions of arylboronic acids with aldehydes, with low Rh(I) catalyst loading, are described. We also found that the reaction of arylboronic acids with α,β-unsaturated aldehydes greatly depends on the solvent and the steric hindrance of the reagents/substrates.