Catalytic Asymmetric (4+3) Cyclizations of In Situ Generated ortho-Quinone Methides with 2-Indolylmethanols.

The first catalytic asymmetric (4+3) cyclization of in situ generated ortho-quinone methides with 2-indolylmethanols has been established, which constructed seven-membered heterocycles in high yields (up to 95 %) and excellent enantioselectivity (up to 98 %). This approach not only represents the first catalytic asymmetric (4+3) cyclization of o-hydroxybenzyl alcohols, but also enabled an unprecedented catalytic asymmetric (4+3) cyclization of 2-indolylmethanols. In addition, a scarcely reported catalytic asymmetric (4+3) cyclization of para-quinone methide derivatives was accomplished.