Synthesis of Benzofuro[3,2-b]indol-3-one Derivatives via Dearomative (3 + 2) Cycloaddition of 2-Nitrobenzofurans and
Wei-Cheng Yuan1,2, Hai-Ying Zeng1,2, Yan-Ping Zhang1
1Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China.
Abstract:
An efficient dearomative (3 + 2) cycloaddition of para-quinamines and 2-nitrobenzofurans has been developed. This reaction proceeds smoothly under mild conditions and affords a series of benzofuro[3,2-b]indol-3-one derivatives in good to excellent yields (up to 98%) with perfect diastereoselectivities (all cases > 20:1 dr). The scale-up synthesis and versatile derivatizations demonstrate the potential synthetic application of the protocol. A plausible reaction mechanism is also proposed to account for the observed reaction process. This work represents the first instance of the N-triggered dearomative (3 + 2) cycloaddition of 2-nitrobenzofurans.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Cycloaddition Reactions: MO Requirements for Thermal Activation
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation


