Related Experiment Video
Updated: Aug 10, 2025

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Development of a Non-Directed Petasis-Type Reaction by an Aromaticity-Disrupting Strategy
Kevin J Gonzalez1, Alexander W Rand1, Brian M Stoltz1
1Division of Chemistry and Chemical Engineering, California Institute of Technology 1200 E., California, Blvd, MC 101-20, Pasadena, CA 91125, USA.
Abstract:
The Petasis-type reaction, which couples an imine and boronic acid, is an important tool for C-C bond formation in organic synthesis. However, the generality of this transformation has been limited by the requirement for a directing heteroatom to enable reactivity. Herein, we report the development of a non-directed Petasis-type reaction that allows for the coupling of trifluoroborate salts with α-hydroxyindoles. By disrupting aromaticity to generate a reactive iminium ion, in conjunction with using trifluoroborate nucleophiles, the method generates a new C-C bond without the need for a directing group. This reaction is operationally simple, providing α-functionalized indoles in up to 99 % yield using sp, sp2 , and sp3 -hybridized trifluoroborate nucleophiles. Finally, this reaction is applied as a novel bioconjugation strategy to link biologically active molecules and toward the convergent synthesis of non-natural heterodimeric bisindole alkaloid analogs.
Related Concept Videos
Nucleophilic Aromatic Substitution: Elimination–Addition
Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
Electrophilic Aromatic Substitution: Overview
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

