One-pot synthesis of cis-isoquinolonic acid derivatives via three-component reaction of homophthalic anhydride with aldehydes and amines using ytterbium(III) triflate as catalyst

Ytterbium(III) triflate efficiently catalyzes the one-pot reaction of homophthalic anhydride with aldehydes and amines at ambient temperature to afford the corresponding cis-isoquinolonic acid derivatives in good to excellent yields with high diastereoselectivity. This method provides a novel and much improved modification of the three-component reaction in terms of mild reaction conditions, short reaction times, clean reaction profiles, small quantity of catalyst, and simple work-up procedure. Another important feature of this method is that the catalyst can be easily recovered from the aqueous layer after the reaction and can be reused with no loss of activity.