Enantioselective Multicomponent Synthesis of Propargylamines

Significance

A one-pot three-component coupling reaction is reported using the i-Pr-pybox-diPh ligand. An increase in the enantioselectivity and decrease in reaction time to prepare chiral propargylamines (with i-Pr-pybox: < 45% ee, 4 d) was observed. Noteworthy for the catalytic system is the absence of a dehydrating agent often needed to pre-form the imine. The reaction showed consistently high enantioselectivity, independent of the nature of the aryl substituents on the three reacting components. The only non-aromatic variations were made on the terminal alkyne moiety (8), which remained unaffected by the aryl substitution, but where alkyl groups afforded lower ee values.