3-(Hydroxymethyl)phenylboronic Acid | CAS 87199-15-3 | ≥98%

3-(Hydroxymethyl)phenylboronic Acid (3-Hydroxymethylbenzeneboronic Acid, 3-Boronobenzyl Alcohol) is a bifunctional arylboronic acid building block with a meta-substitution pattern placing the boronic-acid and benzylic alcohol handles at a 120° disposition on the phenylene unit.

The product may contain small amounts of the cyclic anhydride 3-(hydroxymethyl)phenylboroxine; under aqueous or basic coupling conditions the two forms re-equilibrate and the impact on yield is minor.

Applications and Reactions

• Suzuki–Miyaura coupling: couples with aryl, heteroaryl, and alkenyl halides or triflates under standard Pd-catalysed aqueous-basic conditions to give biaryl, heterobiaryl, and styrene-type products; the meta-benzylic alcohol is typically retained as a post-coupling functional handle.
• Hydroxymethyl handle on the free boronic acid: standard benzylic alcohol chemistry applies — Appel halogenation, mesylation, tosylation, Mitsunobu, etherification, esterification, carbamate formation, controlled oxidation to the aldehyde or acid — within the compatibility limits of any onward steps in the target molecule; the unprotected boronic acid should not be assumed to survive strongly oxidising conditions such as Jones.
• Reversible boronate ester formation with diols: as an arylboronic acid, forms reversible covalent boronate esters with cis-1,2- and 1,3-diols, saccharides, and catechols in aqueous media. The meta-hydroxymethyl group provides an additional alcohol handle for scaffold or surface attachment.
• Dynamic-covalent boronate–diol networks: class-level arylboronic-acid chemistry. The reversible boronate–diol bond underpins self-healing polymers, pH- and glucose-responsive hydrogels, and crosslinked dynamic networks; the bifunctional meta-hydroxymethyl architecture provides an additional anchoring site for orthogonal modification.
• Copper-catalysed transformations of arylboronic acids in water: general Cu2O/NH3-in-water method converting arylboronic acids into aryl iodides, azides, sulfones, phenols, anilines, and nitroarenes under air using inexpensive salt and ammonia functional-group sources.
• Copper-mediated trifluoromethylation: this compound has been reported as a substrate in copper-mediated trifluoromethylation reactions of arylboronic acids, giving access to the corresponding meta-trifluoromethylbenzyl alcohol framework under Cu/CF3-source conditions outside the conventional Pd/aryl-halide manifold.
• Chan–Lam-type C–N and C–O coupling: class-level arylboronic-acid chemistry. With Cu(OAc)2 or related Cu(II) systems and an amine, amide, sulfonamide, carbamate, phenol, or selected alcohol partner under mild aerobic conditions, gives the corresponding N-aryl or O-aryl product.
• Petasis borono-Mannich reaction: class-level arylboronic-acid chemistry. The boronic acid acts as the aryl donor in a three-component coupling with an amine and an aldehyde, glyoxylic acid, or α-hydroxy aldehyde partner to give arylated amines, including α-aryl glycine and β-amino alcohol scaffolds.
• Protected boronate derivatives: the corresponding pinacol ester (Bpin, CAS 443776-76-9) is commercially documented. Other boronate forms, including MIDA boronate, neopentyl glycol ester, Bdan, trifluoroborate, and MEA boronate, are class-level options to be selected case by case depending on the workflow. MIDA boronates in general are chromatographically tractable, air-stable boron surrogates compatible with iterative Suzuki coupling under slow-release conditions; Bpin derivatives are commonly used protected boronate forms for handling and cross-coupling workflows.
• Non-classical arylation pathways: class-level arylboronic-acid chemistry. Arylboronic acids can participate in Suzuki–Miyaura-type coupling with arenediazonium salts under Pd catalysis, and in base-free Suzuki-type arylation with pentavalent triarylantimony diacetates, providing alternative access to biaryl products outside the usual aryl halide/triflate electrophile set.
• Ipso-halodeboronation: class-level arylboronic-acid chemistry. With NBS, NCS, or NIS, or related halogenating systems, the C–B bond can be converted to C–X to access the corresponding aryl halide; for this substrate, compatible conditions would lead to the 3-halobenzyl alcohol framework.
• Oxidative ipso-hydroxylation: class-level arylboronic-acid chemistry. With H2O2, oxone, sodium perborate, or copper-/photo-mediated aerobic hydroxylation conditions, the C–B bond can be replaced by C–OH to give the corresponding phenol — here, 3-hydroxybenzyl alcohol.

Further Reading

For boronic acids, boronic esters, protodeboronation, boroxine content, and Suzuki–Miyaura reagent selection, see NorrChemica's Lab Journal guide: Choosing Your Boron Source for Suzuki–Miyaura Coupling.