ChemInform Abstract: Enantioselective Gold-Catalyzed Intermolecular [2 + 2] versus [4 + 2]-Cycloadditions of 3-Styrylindoles with N-Allenamides: Observation of Interesting Substituent Effects.

When the substituents on the nitrogen of indoles are hydrogen or electron-donating groups, such as methyl [e.g. (I)], benzyl, allyl groups, [2 + 2]-cycloaddition takes place to give the products [e.g. (III)] as (Z)-isomers with excellent yields and enantioselectivities. [ABSTRACT FROM AUTHOR]