Indol-2-yltributylstannane: A Versatile Reagent for 2-Substituted Indoles

A general method for 2-substituted indoles via the palladium-catalyzed coupling of indol-2-ylstannanes is described. (N-Methylindol-2-yl)tributylstannane (1) reacts with a variety of electrophiles under very mild conditions. [N-tert-Butoxycarbonyl)indol-2-yl]tributylstannane (3) is much less reactive in the coupling reactions and reacts only with certain activated electrophiles. [N-[[(Trimethylsilyl)ethoxy]methylindol-2-yl]tributylstannane (4) behaves similarly to 1 and the removal of the [(trimethylsilyl)ethoxy]methyl group can be achieved with tetra-n-butylammonium fluoride in DMF in the presence of ethylenediamine