Functional-group translocation of cyano groups by reversible C-H sampling

Area of Science:

• Organic Chemistry
• Photocatalysis
• Synthetic Methodology

Background:

• Functional group interconversion is a cornerstone of synthetic chemistry.
• Transformations altering only functional group location (translocation) are less explored than conventional interconversions.
• Site-selective C-H functionalization is challenging, especially without pre-functionalization or directing groups.

Purpose of the Study:

• To develop a novel method for functional-group translocation, specifically for cyano (CN) groups.
• To enable the direct positional exchange between a CN group and an unactivated C-H bond.
• To demonstrate the utility of this reaction in synthesizing complex molecules and bioactive building blocks.

Main Methods:

• Development of a photocatalytic, reversible C-H sampling strategy.
• Application to common nitriles for CN group translocation.
• Exploration of transannular CN translocation in cyclic systems.

Main Results:

• Successful demonstration of 1,4-CN translocation with high fidelity, often overcoming inherent site selectivity.
• Access to valuable cyclic structures via direct transannular CN translocation.
• Concise synthesis of building blocks for bioactive molecules utilizing CN translocation.
• Combination with C-H cyanation to access unconventional C-H derivatives.

Conclusions:

• The reported photocatalytic CN translocation reaction provides a new tool for site-selective C-H functionalization.
• This method achieves site-selective transformations without requiring a site-selective C-H cleavage step.
• The reaction expands the synthetic chemist's toolkit for creating complex organic molecules.