Visible Light Mediated Metal-free Thiol–yne Click Reaction

The carbon–sulfur bond formation reaction is of paramount importance for functionalized materials design, as well as for biochemical applications. The use of expensive metal-based catalysts and the consequent contamination with trace metal impurities are challenging drawbacks of the existing methodologies. Here, we describe the first environmentally friendly metal-free photoredox pathway to the thiol–yne click reaction. Using Eosin Y as a cheap and readily available catalyst, C–S coupling products were obtained in high yields (up to 91%) and excellent selectivity (up to 60:1). A 3D-printed photoreactor was developed to create arrays of parallel reactions with temperature stabilization to improve the performance of the catalytic system.

Reference: Chem. Sci., 2016, 7, 6740-6745.

DOI: 10.1039/C6SC02132H

On-line version: http://doi.org/10.1039/C6SC02132H