Larock RC,
*,
Yum EK,
Refvik MD.
Iowa State University, USA
Synthesis of 2,3-Disubstituted Indoles via Palladium-Catalyzed Annulation of Internal Alkynes.
J. Org. Chem. 1998;
63: 7652-7662
Key words
Larock indole synthesis - palladium catalysis - annulation - regioselectivity - alkyne insertion
Significance
In 1998, Larock and co-workers reported a palladium-catalyzed coupling of 2-iodoanilines with internal alkynes to afford 2,3-disubstituted indoles; an important heterocyclic scaffold. The reaction proceeds under mild conditions to afford the indole products in good to excellent yields.
Comment
The regioselectivity of the reaction is dependent on both substrate and reaction conditions employed. When more than one equivalent of the chloride is added, the reaction rate is retarded, and there is an increase in the formation of side products.
Review
R. Chinchilla, C. Nájera Chem. Rev.
2014, 114, 1783−1826.
