5-Chlorothiophene-2-boronic Acid Pinacol Ester丨CAS 635305-24-7

Overview

5-Chlorothiophene-2-boronic acid pinacol ester丨CAS 635305-24-7 is a boronic ester derivative of chlorinated thiophene, widely used in cross-coupling chemistry. It combines a heteroaryl unit (thiophene) with both chlorine and pinacol boronate ester, giving it high reactivity and selectivity in Suzuki–Miyaura reactions.

Applications

1. Suzuki–Miyaura Cross-Coupling

Key reagent in Pd-catalyzed cross-coupling reactions with aryl/vinyl halides or triflates.

Used to synthesize biaryl and heteroaryl compounds, particularly in:

Pharmaceutical intermediates

Conjugated polymers

Advanced agrochemical compounds

2. Heterocyclic Compound Synthesis

The thiophene ring is a privileged scaffold in drug design, materials science, and electronics.

5-chlorothiophene derivatives are building blocks for bioactive molecules and semiconducting materials.

3. Precursor in OLED and OFET Materials

Forms thiophene-based polymers and oligomers, which are common in organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs).

4. Agrochemical Discovery

Frequently used in the development of thiophene-derived agrochemicals, offering metabolic stability and activity enhancements.

5. Medicinal Chemistry

The 5-chloro substitution offers synthetic diversification for creating novel analogs in SAR studies.

Common in the synthesis of thiophene-linked kinase inhibitors, anti-inflammatory agents, and antimicrobials.

Benefits

✅ Improved Stability Over Boronic Acids

The pinacol ester form is more stable to air and moisture than boronic acids.

Enables easier handling, storage, and purification.

✅ High Selectivity in Coupling

The sterically hindered pinacol ester still allows efficient transmetallation in Pd-catalyzed reactions.

Gives high yields and regioselectivity even in complex synthetic schemes.

✅ Synthetic Flexibility

The chlorine at position 5 serves as a synthetic handle for further functionalization (e.g., nucleophilic substitution, metal-halogen exchange).

✅ Versatility in Material Science

Thiophene derivatives are well known for their electronic and optical properties.

This compound supports the synthesis of materials with tunable conductivity and fluorescence.

Summary

5-Chlorothiophene-2-boronic acid pinacol ester丨CAS 635305-24-7 is a versatile and stable boronic ester used in Suzuki–Miyaura cross-coupling, particularly for making heteroaryl compounds in the pharmaceutical, materials, and agrochemical industries. Its combination of a boronate ester with a chlorinated thiophene backbone makes it highly effective for creating complex, functional molecules under mild conditions.