Catalytic C–H Activation of Phenylethylamines or Benzylamines and Their Annulation with Allenes
摘要:
Tetrahydro-3-benzazepines and tetrahydroiso-quinolines are synthesized in one,step from allenes and phenylethylamines or benzylamines,Mechanitically, it is assumed that activation of an aromatic ring with Pd(II) occurs, directed by the primary amine, leading to the formation of a palladacycltinto which'ari, allene then undergoes insertion. The resulting, pi-allyl intermediate cyclizes to the products by aniptramolecular allylic alkylation. The process is particularly useful with 2,3-butadienoates and amines having a quaternary carbon at the alpha-position.
Reaction of allylmagnesiumbromide with trifluoromethyl oximes is different than with other Grignard reagents. On the other hand, allylmagnesiumbromide acted as a reducing agent towards trifluoromethyl ketones. By using an excess of this Grignard reagent, an exclusive addition reaction is obtained. A single electron reaction is suggested to explain the reductive process.