Paper-Based Colorimetric Sensor System for High-Throughput Screening of C-H Borylation

Area of Science:

• Organic Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Iridium-catalyzed C-H borylation is a crucial synthetic transformation.
• High-throughput screening is essential for optimizing catalytic reactions.
• Accurate quantification of reagents like bis(pinacolato)diboron is vital for reaction monitoring.

Purpose of the Study:

• To develop a paper-based colorimetric sensor system (PBCSS) for detecting bis(pinacolato)diboron (B2Pin2).
• To apply the PBCSS as a high-throughput screening protocol for Ir-catalyzed C-H borylation.
• To validate the PBCSS's performance against established analytical methods.

Main Methods:

• Development of a PBCSS utilizing colorimetric detection of B2Pin2.
• Screening of 96 ligands for benzene borylation using the PBCSS.
• Testing of 12 selected ligands across five substrates.
• Analysis of reaction mixtures spotted on the PBCSS, measuring gray scale values.
• Conversion of gray scale data to B2Pin2 conversion extents.

Main Results:

• The PBCSS produced a distinct blue-violet color upon reaction.
• Gray scale values from the PBCSS correlated well with B2Pin2 conversion determined by gas chromatography.
• Modified conversion data from the PBCSS showed good correlation with product yields.

Conclusions:

• The developed PBCSS is an effective tool for high-throughput screening in Ir-catalyzed C-H borylation.
• The sensor system provides a reliable and rapid alternative to traditional analytical methods for monitoring B2Pin2 conversion.
• The PBCSS facilitates efficient optimization of catalytic reactions by correlating reagent conversion with product yield.