A new transient directing group diethoxyethyl-l-proline facilitates ortho-arylation of aryl-amines/-amino acids via Pd-catalyzed C(sp2)-H activation

Mono-ortho-arylated arylamines are constituents of various natural products but their syntheses are challenging. This report describes a new synthetic methodology for the ortho-arylation of arylamines and alpha-aromatic amino acids (phenylglycine and phenylalanine) through a Pd-catalyzed C(sp(2))-H activation using the synthetic transient directing group diethoxyethyl-l-proline (DEP). A catalytic amount of diethoxyethyl-l-proline is sufficient to form mono-arylated arylamines as the major products using aryliodides. This method could be useful for the synthesis of various biphenyl amines and novel peptidomimetics.