Photocatalytic Iminothiolation of Alkenes via Monothiocarbonate Oxime Esters

Laskar, Ranjini; Thielemann, Rebecca E.; Knueppe, Janosch; Hoelter, Niklas; Daniliuc, Constantin G.; Glorius, Frank

Abstract

1,2-Aminosulfides are attractive building blocks due to their widespread occurrence in drugs and biologically active compounds. Accessible synthetic routes leading to these motifs have been largely impeded by requiring tailored substrates, harsh reaction conditions and poor atom economy, among other factors. We design a broad range of bifunctional monothiocarbonate oxime esters from commercial thiols and oximes to difunctionalize feedstock alkenes through a mild transformation initiated by energy transfer photocatalysis. The iminyl and thiyl radicals generated by homolysis of our reagents are proposed to participate in a mechanistic pathway involving selective radical–radical cross-coupling and radical chain propagation. Thioxanthone, a metal-free photosensitizer, is used as the catalyst. We demonstrate tolerance of diverse functional groups and relevant post-reaction diversifications to highlight the utility of our robust protocol.