Elemental sulfur as the “S” source: visible-light-mediated four-component reactions leading to thiocyanates

Abstract

An eco-friendly and photocatalyst-free visible-light-promoted four-component reaction of α-diazoesters, elemental sulfur, cyclic ethers and TMSCN is described. A series of diverse organic thiocyanates were conveniently obtained in moderate to good yields at room temperature using odorless elemental sulfur as the “S” source. This protocol effectively avoids the use of metal reagents, strong oxidants, awful smelling materials and harsh reaction conditions. It is noteworthy that α-alkoxyl esters could also be efficiently prepared by a two-component reaction of α-diazoesters with dimethoxyethane under the standard conditions.