Catalytic Asymmetric [4 + 2] Cycloaddition of <i>ortho</i>-Alkenyl Naphthols/Phenols with <i>ortho</i>-Quinone Methides: Highly Stereoselective Synthesis of Chiral 2,3,4-Trisubstituted Chromans

Chiral phosphoric acid-catalyzed biomimetic asymmetric [4 + 2] cycloaddition of <i>ortho</i>-alkenyl naphthols/phenols and <i>ortho</i>-quinone methides (<i>o</i>-QMs) has been demonstrated to afford various important 2,3,4-trisubstituted chromans in high yields with excellent enantio- and diastereoselectivities (up to 99% yield, 99% ee, >20:1 dr). Notably, this methodology not only enabled access to the <i>trans–cis</i> chiral trisubstituted chromans from 1-alkenyl 2-naphthols but also is compatible with 2-alkenyl 1-naphthols and phenols to deliver <i>trans–trans</i> chiral trisubstituted chromans.