Isothiourea‐Catalyzed Enantioselective Functionalisation of Glycine Schiff Base Aryl Esters via 1,6‐ and 1,4‐Additions

Abstract

Abstract The enantioselective α‐functionalisation of glycine Schiff base aryl esters through isothiourea catalysis is successfully demonstrated for 1,6‐additions to para‐quinone methides (21 examples, up to 95 : 5 dr and 96 : 4 er) and 1,4‐ additions to methylene substituted dicarbonyl or disulfonyl Michael acceptors (17 examples, up to 98 : 2 er). This nucleophilic organocatalysis approach gives access to a range of α‐functionalised α‐amino acid derivatives and further transformations of the activated aryl ester group provide a straightforward entry to advanced amino acid‐based esters, amides or thioesters.

Keywords

• 1,6- and 1,4-addition
• α-amino acid derivatives
• enantioselective
• glycine Schiff base
• isothiourea