Palladium-Catalysed Carbo- and Hydroamination of Allenyl Ethers and Aminoallenes : Available Entry to Nitrogen-Containing Benzo-Fused Rings

The Pd-catalysed reactions of allenyl ethers and allenylamines derived from commercially available o-aminophenols and o-nitroaniline have been studied. Using a wide variety of aryl- and heteroaryl halides, carboamination of the allenes led to sequential C–C and C–N bond formation. Both carbo- and hydroamination processes resulted in the formation of nitrogen-containing benzo-fused rings. In the case of aminoallenes arising from o-phenylenediamine, the regioselectivity of the cyclization step was strongly dependent on the protecting group tethered to the nitrogen atoms, allowing the formation of five- and seven-membered rings.