Triflic Acid-Promoted 1,2-Amino Migration Reactions in α-Arylaminoacrylamides: Access to Substituted β-Aminoamides.

A straightforward synthesis of substituted β-aminoamides from α-arylamino-β-hydroxyacrylamides, α-arylamino-β-oxoamides, or their tautomeric mixture has been described. The ( E )-enol triflate intermediates are readily generated in situ from these substrates in the presence of triflic anhydride (Tf 2 O) and triethylamine (Et 3 N) in a chemoselective manner and undergo triflic acid (TfOH)-promoted cyclization and ring-opening reactions with alcohols to deliver the desired products. The one-pot two-step synthetic protocol features the use of readily available starting materials, mild reaction conditions, high chemoselectivity, operational simplicity, and a wide range of synthetic potential of the products.