Diastereoselective Ugi reaction for the synthesis of unnatural amino esters

Abstract

Multicomponent Reactions (MCR) are useful reactions to obtain complex products by the simple mixture of 3 or more reactants. The classic Ugi reaction (4-UCR) involves a mixture of an amine, aldehyde, isocyanide and a carboxylic acid, giving peptoides as products. Some modifications of this reaction have been reported, among which the use of amino acids and Lewis acids, such as titanium (IV) chloride, to induce stereoselectivity in good ratio. In this work we demonstrate the efficiency of different Lewis acids in the modified Ugi reaction and good levels of diastereoselectivity and yields in the synthesis of unnatural secondary amino esters.