A catalytic asymmetric [4+2] cycloaddition of ortho-quinone methide imines in situ generated from o-aminobenzyl alcohols with o-hydroxystyrenes has been established under the catalysis of chiral phosphoramide, which afforded chiral tetrahydroquinolines in moderate to good yields, good enantioselectivities, and excellent diastereoselectivities (up to 82% yield, 93:7 er, all >95:5 dr). In this catalytic asymmetric [4+2] cycloaddition, the hydrogen-bonding interaction between chiral phosphoramide and two substrates was proposed to play a crucial role in controlling the enantioselectivity. This reaction not only provides a useful approach for constructing chiral tetrahydroquinoline frameworks, but also demonstrates the great practicability of ortho-quinone methide imines in catalytic asymmetric cycloadditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.