[reaction: see text] The palladium-catalyzed reaction of ethyl3-(o-trifluoroacetamidophenyl)-1-propargyl carbonate with piperazines in the presence of Pd(PPh(3))(4) in THF at 80 degrees C affords 2-(piperazin-1-ylmethyl)indoles in excellent yields. Good to excellent yields are also obtained with other secondary amines.
The reaction of ethyl3-(o-trifluoroacetamidoaryl)-1-propargylic carbonates with primary or secondary amines in the presence of Pd 2 (dba) 3 , dppf, and carbon monoxide in THF at 80 °C provides ready access to free-NH indole 2-acetamides. The reaction can be applied to the synthesis of free-NH indole 2-acetic acid methyl esters.
The reaction of ethyl3-(o-trifluoroacetamidophenyl)-1-propargyl carbonates with formate anions in the presence of Pd(PPh3)4 affords 2-alkylindoles in good to excellent yields.