Catalytic asymmetric indolization by a desymmetrizing [3 + 2] annulation strategy.

A new catalytic asymmetric indolization reaction by a desymmetrizing [3 + 2] annulation strategy is developed. The reaction proceeds a rhodium-catalyzed enantioposition-selective addition/5--trig cyclization/dehydration cascade between -amino arylboronic acids and 2,2-disubstituted cyclopentene-1,3-diones to produce -unprotected cyclopenta[]indoles bearing an all-carbon quaternary stereocenter in high yields with good enantioselectivities. A quantitative structure-selectivity relationship (QSSR) model was established to identify the optimal chiral ligand, which effectively controlled the formation of the stereocenter away from the reaction site.