Asymmetric Dearomatizative Diels–Alder Reaction for the Construction of Hydrodibenzo[b,d]furan Frameworks with Tetrasubstituted Stereogenic Centers

Constructing fused hydrodibenzofuran architectures bearing a tetrasubstituted stereogenic center adjacent to an O atom is extremely difficult. Here we have developed an asymmetric dearomatizative Diels–Alder reaction using novel 2‐(3‐vinylbenzofuran‐2‐yl)ethan‐1‐one substrates and 3‐olefinic 7‐azaoxindoles. The reaction proceeds via in situ generation of a HOMO‐raised formal trienamine species with a chiral primary amine catalyst, producing highly complex tetrahydrodibenzo[b,d]furan derivatives with vicinal tetrasubstituted stereogenic centers in moderate yields with excellent stereoselectivity (dr>19:1, up to 98% ee).