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

• Published in: Advanced synthesis & catalysis Vol. 359; no. 19; pp. 3341 - 3346
• Main Authors: Jiang, Xiao‐Li, Liu, Si‐Jia, Gu, Yu‐Qi, Mei, Guang‐Jian, Shi, Feng
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 04.10.2017; Wiley Subscription Services, Inc
• Subjects: asymmetric catalysis; Asymmetry; Cascade chemical reactions; Catalysis; Chemistry; Chemistry, Applied; Chemistry, Organic; cyclization; organocatalysis; ortho-quinone methides; Oxidation; Physical Sciences; Scaffolds; Science & Technology; spirooxindole; spirooxindole; ENANTIOSELECTIVE SYNTHESIS; ANNULATION; OXINDOLES; asymmetric catalysis; cyclization; organocatalysis; CYCLOADDITION; ACTIVATION STRATEGY; ACID CATALYSIS; CONSTRUCTION; ortho-quinone methides; FRIEDEL-CRAFTS REACTION; ADDITIONS; IN-SITU
• ISSN: 1615-4150; 1615-4169
• DOI: 10.1002/adsc.201700487

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.