The three-component Ugi reactions of 3,4-dihydroisoquinolines, isocyanides and acids
furnished 2-acyl-N-substituted-1,2,3,4-tetrahydroisoquinoline-1-carboxamides in moderate
to good yields. Chiral, nonracemic acids induced only poor diastercoselectivities
in the condensations. Hydrolysis of the Ugi carboxamides gave the corresponding 1,2,3,4-tetrahydroisoquinoline-1-carboxylic
acids, which due to their ready ability to undergo racemization, were obtained as
racemic mixtures or with low enantiomeric excesses.