Efficient and Sustainable One-pot Synthesis of alpha-Carbonyl Homoallylic Alcohols from Benzaldehyde and Allylic Alcohols Using both NHC and Nickel Catalysts

International audienceα-carbonyl homoallylic alcohols have been synthesized in a one-pot reaction from benzaldehyde and allylic alcohols. The nickel-catalyzed allylation of α-hydroxyketones has first been studied and allowed the identification of Ni(cod)2/dppf as the most suitable catalytic system. The tandem reaction that combines the benzoin condensation of aldehydes (synthesis of α-hydroxyketones) promoted by the 1,3-dimethylimidazolium chloride/DBU system and the nickel-catalyzed allylic alkylation with allylic alcohol has been realized in EtOH as green solvent. The reaction is 100 % atom-economical and water is formed as sole by-product. A broad scope of different benzaldehyde derivatives as well as various allylic alcohols is also described