4,​4,​5,​5-​Tetramethyl-​2- ​[4-​(3,​6,​9,​12-​tetraoxatridec-​1-​yloxy)​phenyl] ​-1,​3,​2-​dioxaborolane

Name: 4,​4,​5,​5-​Tetramethyl-​2-​[4-​(3,​6,​9,​12-​tetraoxatridec-​1-​yloxy)​phenyl]​-1,​3,​2-​dioxaborolane 

Molecular Formula: C21H35BO7 

CAS#: 1181210-11-6 

SMILES: CC(O1)(C)C(C)(C)OB1C2=CC=C(OCCOCCOCCOCCOC)C=C2 

MDL#: MFCD22381091 

Catalog#: AMTB1292-TE19 

Molecular weight: 410.31 g/mol 

Other names: 

• 4-(3,6,9,12-tetraoxatridecyloxy)phenylboronic acid pinacol ester  

• PEG4 phenyl boronic ester  

• PEG4 aryl boronate linker 

Fields of Interest: Suzuki–Miyaura cross-coupling, synthetic chemistry, materials sciences, medicinal chemistry, drug discovery, bioconjugation 

For complementary coupling partners, see aryl halide or heteroaryl halide intermediates compatible with Suzuki–Miyaura reactions. 

Background 

4,4,5,5-Tetramethyl-2-[4-(3,6,9,12-tetraoxatridec-1-yloxy)phenyl]-1,3,2-dioxaborolane (CAS 1181210-11-6) is a boronic ester-functionalized PEG derivative featuring a PEG4 spacer linked to an aryl boronic acid pinacol ester moiety. The polyethylene glycol segment provides hydrophilicity, flexibility, and compatibility with aqueous and organic environments, while the boronic ester functionality serves as a stable and reactive partner for Suzuki–Miyaura cross-coupling reactions. Compared to boronic acids, pinacol boronate esters offer improved stability and handling, making them widely used intermediates in modern synthetic chemistry. This compound represents a versatile building block within a comprehensive portfolio of functionalized PEGs designed for modular assembly and carbon–carbon bond formation. 

Applications 

This PEGylated aryl boronic ester is commonly used in cross-coupling chemistry, materials science, and drug discovery applications where PEG solubility and Suzuki-compatible reactivity are required. Typical uses include palladium-catalyzed coupling with aryl or vinyl halides to construct PEG-linked aromatic systems, preparation of functional polymers and advanced materials, and synthesis of pharmaceutical intermediates. The Suzuki–Miyaura reaction is one of the most widely used methods for forming carbon–carbon bonds between organoboron reagents and electrophiles, enabling the construction of complex molecular architectures under relatively mild conditions. As part of a robust functionalized PEG product line, this boronic ester PEG linker supports modular design strategies in specialty chemical synthesis, diagnostics, and advanced materials development. 

Appearance: Colorless liquid 

Purity: 97% 

Storage: Room Temp 

Solubility: Dichloromethane, Chloroform, Acetonitrile 

Literature:  

• Journal of Organic Chemistry, 2024, vol. 89, # 1, p. 163 – 173 

• Journal of Materials Chemistry C, 2016, vol. 4, # 40, p. 9576 – 9580