Copper-catalyzed asymmetric propargylic substitution with salicylaldehyde-derived imine esters

Copper-catalyzed asymmetric propargylic substitution with salicylaldehyde-derived imine esters and propargylic carbonates has been successfully realized, generating a wide range of chiral amino acid derivatives containing propargylic groups with excellent results (up to 95% yield and 94% ee). The ortho-hydroxy group of the salicylaldehyde-derived imine esters is crucial to increase the reactivity and stabilize the azomethine ylide, which may be due to the formation of an intramolecular hydrogen bond between the hydroxyl group and the imine group. A series of synthetic transformations were carried out to access other important chiral compounds, which displayed the synthetic versatility.

Automated summary

In this study, copper-catalyzed asymmetric propargylic substitution was successfully achieved using salicylaldehyde-derived imine esters and propargylic carbonates, resulting in a wide range of chiral amino acid derivatives containing propargylic groups. The ortho-hydroxy group of the salicylaldehyde-derived imine esters played a crucial role in increasing reactivity and stabilizing the azomethine ylide.