Synthesis of o-Arylenediamines through Elemental Sulfur-Promoted Aerobic Dehydrogenative Aromatization of Cyclohexanones with Arylamines
摘要:
Herein, the first elemental sulfur-promoted aerobic dehydrogenative aromatization of cyclohexanones is described that provides novel access to synthetically useful o-arylenediamines. This protocol complements previous palladium- and iodine-catalyzed diarylamine formation from cyclohexanones and anilines.
afforded a series of five new dihydrophenazines instead of the expected cyclohexadiene‐1,2‐diimines. The reaction most likely proceeds via a 1,6‐electrocyclic path and provides a convenient access to an important class of nitrogen heterocycles. Subsequent treatment of the mesityl derivative with chloromethyl pivalate and silver triflate led to the corresponding benzimidazolium salt.