Protein phosphorylation is a ubiquitous post-translational modification, which often acts as a switch to proteins' activation and is frequently perturbed in diseases. Although many general phospho-protein detection tools are available, none of them offers information about the relative spatial arrangement of phosphorylated residues. Specifically, proximally phosphorylated residues are hallmarks of certain activated disease-relevant proteins. We herein report the first turn-on fluorescent sensor for the selective detection of proximally phosphorylated protein sites, suitable for application in both aqueous solutions and polyacrylamide gels.

This review summarizes new methodology for the synthesis of α-aminoboronates, including asymmetric synthetic methods and mechanistic explanations of reactivity. Applications of α-aminoboronates as versatile synthetic building blocks are also discussed.

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Peptide/boronic acid conjugates are attractive scaffolds for chemical probe discovery and drug design. There are only a few reactions that allow for rapid incorporation of boron into peptides. Herein, we report a new approach towards the synthesis of peptide β‐aminoboronic acids on solid support using 2‐chlorotrityl resin and solid‐phase peptide synthesis techniques with only one purification required. Evaluation of model compounds demonstrate the stability of peptide boronic acids toward degradation at physiological pH. This straightforward conjugation process should allow access to a wide range of peptide boronic acid scaffolds for both synthetic and medicinal use.

Our ongoing search for underdeveloped functional group combinations has brought to light a-fluorinated aminoalkylboronic acids, a new class of molecules featuring the B-CF linkage. These compounds can now be generated from secondary amines and a-boryl aldehydes through electrophilic fluorination of boryl enamines or enamides. Fluorinated baminoalkylboronic acids show no signs of degradation under ambient conditions. We present evidence for the involvement of chair-like motifs, favored over the acyclic forms by up to 1.7 AE 0.1 kcal mol À1 in water and held together by an amine-boronate hydrogen bond. Fluorinated b-aminoalkylboronic acids are stable over a wide pH range and are characterized by a pK a of 3.4, which is the lowest of any alkylboronic acid.