Microwave-assisted organic synthesis: scale-up of palladium-catalyzed aminations using single-mode and multi-mode microwave equipment

Batch wise scale-up of Buchwald-Hartwig aminations under microwave irradiation has been investigated for the first time. Multi-mode (microSYNTH and MARS) (several vessels irradiated in parallel per batch) as well as single-mode (Discover) (one vessel irradiated per batch) platforms can be successfully used for this purpose with trifluoromethylbenzene (benzotrifluoride: BTF) as amination solvent. The obtained yields indicate a direct scalability in BTF for all the studied aminations. The Voyager equipment (based on a Discover platform) is the most convenient system since it allows an automatic continuous batch wise production without the necessity to manually load and unload reaction vessels.