ИСТИНА

Multiple bonds of alkynes and alkenes are carriers of chemical energy, which is widely utilized in organic synthesis. However, while thermodynamics of addition reactions to the alkynes and alkenes is favorable, control of selectivity remains challenging in various systems. Widely used approaches of overcoming this difficulty are applying transition metals for coordination and alignment reagents in necessary order or usage of substrates with different polarities. In this work1 we demonstrate a system, where chemoselectivity is determined by the nature of thiyl radical, triple and double C-C bonds. Regio- and stereoselectivity is encoded in presence of aromatic substituents in reagents. This behavior of the reagents can be achieved due to fine tuning of the mild conditions of the reaction mixture. Most of the side processes can be suppressed by complete deprotonation of the thiol with formation of corresponding anion, decrease of its nucleophilicity in protic solvent and selection of suitable photocatalyst and temperature for the control of radical transformations. Mechanism of the thiol-yne-ene reaction was confirmed by detection of adducts of the intermediates by ESI-HRMS, EPR and NMR spectroscopy, estimation of the quantum yield, fluorescence quenching experiments and DFT calculations.