Metal-free stereoselective intramolecular oxyamination of alkynes using a robotic and rapid photocatalytic synthesis and screening system

Abstract

A unique metal-free and 100% atom-economical method for intramolecular oxyamination of alkynes with high stereoselectivity via visible light photocatalysis is developed. Utilizing a robotic and rapid photocatalytic synthesis and screening system capable of anhydrous and oxygen-free flow synthesis, the standard reaction conditions were extensively investigated and optimized with reduced sample consumption, and an inexpensive and efficient organic photosensitizer was rapidly and successfully found. Starting from inexpensive, widely and readily available propargyl alcohol feedstock materials, single Z configuration 2-aminoprop-1-ene-1,3-diol derivatives could be obtained with good functional group compatibility and broad substrate scope. A possible mechanism involving a nitrogen radical process and nucleophilic attack was proposed based on the radical inhibition experiment and the cross-over experiment.