Catalytic asymmetric formal (2 + 3) cycloaddition involving methyl-substituted 2-indolylmethanols

A catalytic asymmetric formal (2 + 3) cycloaddition of methyl-substituted 2-indolylmethanols was established, which delivered various chiral pyrroloindoles in overall high yields with excellent diastereoselectivities and good enantioselectivities.