Activation of primary amines by copper(I)-based Lewis acid promoters in the solventless synthesis of secondary propargylamines

Primary amines are activated by copper(I)-based Lewis acid promoters in an A3-coupling one-pot solventless reaction with aldehydes and phenylacetylene for the synthesis of secondary propargylamines. The reaction is promoted by a CuSo4/NaI system, a practical precursor of the in situ generated effective CuI/I2 system, that worked well, but only in a restricted number of examples substitution of I2 with CeCl3.7H2O in a one-pot two-step reaction provided good yields and a wider applicability, with the added value given by a safe procedure.