Synthesis of functionalized pyrrole and indole derivatives through carbometallation of lithiated double bonds

Bis(2-lithioallyl)amines derived from bis(2-bromoallyl)amines undergo intra molecular carbometallation of a lithiated double bond, giving dilithiated d ihydropyrroles. The cyclizations are promoted by N,N,N ' ,N ' -tetramethyle thylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functio nalized heterocycles, Although 2-lithioallylamines do not suffer intermolec ular carbometallation, dimerization products are obtained with their copper or zirconium derivatives. Finally, the application of this new reaction to 2-lithio-N-(2-lithioallyl)anilines leads to S-lithiomethylindole derivativ es, which are transformed to functionalized indole derivatives by reaction with electrophiles.