Planar chiral arene ruthenium complexes derived from R-carvone

Abstract

Natural R-carvone was converted into chiral 1-aryl-2-methyl-5-isopropyl-cyclohexadienes using a cross-coupling reaction as a key step. These dienes react with RuCl₃ to give planar-chiral complexes [(arene)RuCl₂]₂ in 70–75% yields. Complex [(1-Ph-2-Me-5-ⁱPr-C₆H₃)RuCl₂]₂, a chiral analogue of the classical catalyst [(cymene)RuCl₂]₂, promotes C–H activation of N-methoxy-benzamide and intramolecular insertion of a diazo compound into a C–H bond, but gives products with low stereoselectivity.