Catalytic Asymmetric [4+1] Cyclization of ortho‐Quinone Methides with 3‐Chlorooxindoles

In this work, we established catalytic asymmetric [4+1] cyclization of ortho‐quinone methides (o‐QMs) with 3‐chlorooxindoles and a catalytic asymmetric domino oxidation/[4+1] cyclization reaction of 2‐alkylphenols with 3‐chlorooxindoles, which constructed a spirooxindole‐based 2,3‐dihydrobenzofuran scaffold in good yield (up to 97%), with excellent diastereoselectivity (up to >95:5 dr) and high enantioselectivity (up to 99% ee). This work is not only the first highly enantioselective [4+1] cyclization of o‐QMs but has also realized the first catalytic asymmetric domino [4+1] cyclization of o‐QMs. In addition, both of the reactions provide efficient stereoselective methods for constructing spirooxindole‐based 2,3‐dihydrobenzofuran scaffolds with optical purity.