Continuous Flow Synthesis of Sulfur‐ and Selenium−NHC Compounds (NHC=N‐Heterocyclic Carbene)

Abstract

AbstractThe first continuous flow syntheses of sulfur‐ and selenium−NHC (NHC=N‐heterocyclic carbene) adducts in unprecedented short reaction times and high yields are reported. The importance of these species in coordination chemistry or as efficient tools for determining the π‐acceptor character of NHC ligands make any improvement in their synthesis a worthy goal. Thiourea derivatives bearing both saturated and unsaturated NHCs were obtained using NEt3 as a weak base (homogeneous setup) in conjunction with a bed of elemental sulfur (S8). The synthetic route proving optimal for selenoureas involves the use of a simple Se/K2CO3 heterogeneous microreactor design.