Lewis Acid-Controlled Regioselective Phosphorylation of 2‑Indolylmethanols with Diarylphosphine Oxides: Synthesis of Highly Substituted Indoles

The Lewis acid-promoted phosphorylation
of 2-indolylmethanols with diarylphosphine oxides is described. The
regioselectivity of the reaction can be modulated by the choice of
rare earth metal Lewis acid, offering a highly selective approach
to structurally diverse indole derivatives in up to 97% yield for
over 50 examples. This strategy features high selectivity, good functional
group tolerance, and easy scalability. The utility of this method
is further highlighted by facile modification of the products to access
novel indole-based phosphine ligand.