Selective 1,2-Aminoisothiocyanation of 1,3-Dienes Under Visible-Light Photoredox Catalysis.

Selective three-component 1,2-diamination of 1,3-dienes with concurrent introduction of two orthogonally protected amino groups remains unknown despite its significant synthetic potential. We report herein that reaction of conjugated dienes with N-aminopyridinium salts and TMSNCS affords 1,2-aminoisothiocyanation products in a highly chemo- and regio-selective manner under mild photoredox catalytic conditions. Mechanistic studies indicate that the facile isomerization of allyl thiocyanates to allyl isothiocyanates under photocatalytic conditions is responsible for the selective formation of the observed products. The mild isomerization protocol is expected to find applications in the synthesis of allyl isothiocyanates in a broad sense.