Rhodium-catalysed decarbonylative C(sp2)-H alkylation of indolines with alkyl carboxylic acids and carboxylic anhydrides under redox-neutral conditions

We developed a rhodium-catalysed decarbonylative C(sp(2))-H alkylation method for indolines. This reaction facilitates the use of alkyl carboxylic acids and their anhydrides as a cheap, abundant and non-toxic alkyl source under redox-neutral conditions, featuring the introduction of a primary alkyl chain, which cannot be addressed by previous radical-mediated decarboxylative reaction. Through a mechanistic investigation, we revealed that an initially formed C-7 acylated indoline was transformed into the corresponding alkylated indoline via a decarbonylation process.

Automated summary

We developed a new catalytic system for the decarbonylative C(sp(2))-H alkylation of indolines. This method allows for the use of cheap, abundant, and non-toxic alkyl carboxylic acids and their anhydrides as an alkyl source, introducing a primary alkyl chain that was not possible with previous methods.