Synthesis of functionalized pyrrole and indole derivatives through carbometallation of lithiated double bonds.
Bis(2-lithioallyl)amines derived from bis(2-bromoallyl)amines undergo intramolecular carbometallation of a lithiated double bond, giving dilithiated dihydropyrroles. The cyclizations are promoted by N,N,N',N'-tetramethylethylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functionalized heterocycles. Although 2-lithioallylamines do not suffer intermolecular 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 3-lithiomethylindole derivatives, which are transformed to functionalized indole derivatives by reaction with electrophiles.
Fañanás
F J
FJ
Instituto Universitario de Química Organometálica Enrique Moles, Universidad de Oviedo, Spain.
Granados
A
A
Sanz
R
R
Ignacio
J M
JM
Barluenga
J
J