Hermann-Beller catalyst

De Meijere and coworkers developed a nice example where three C-C-bonds are formed in one domino process [36]. Thus, reaction of 6/1-48 with the Hermann-Beller catalyst 6/1-15 led to 6/1-50 as the only product (Scheme 6/1.10). It can be assumed that the Pd-compound 6/1-49 is an intermediate. 

The first palladium-catalyzed coupling between a secondary amine and an aryl chloride was described by Beller, Hermann and co-workers in 1997 [70]. Use of palladacycle 12 as catalyst resulted in C-N bond formation in good yield for several secondary amines and electron-deficient aryl chlorides, Eq. (40). In these transformations, varying amounts of the regioisomeric product was observed, indicative that to some degree the reaction proceeds via a benzyne intermediate. 

---