N‐heterocyclic carbenes. IV.¹synthesis of symmetrical and unsymmetrical imidazolium salts with abietane moiety

Methyl 12‐chloromethyl‐dehydroabie‐tate reacts with 1‐benzyl‐ and 1‐arylimidazoles to give unsymmetrically substituted imidazolium chlorides ( 1a–i ), with abietane moiety. Starting from methyl 12‐aminodehydroabietate, symmetrically substituted diterpene‐based salts of imidazolinium ( 4 ) and imidazolium ( 5 ) were synthesized. Anion exchange afforded corresponding ( 1e ·BF 4 ) and ( 1e ·PF 6 ). The new compounds were tested as ligands for a Pd‐catalyzed Suzuki‐Miyaura reaction. The molecular structure of ( 1e ) is reported.