Arylboronic Pinacol Esters Research Articles

Copper-Mediated Radiobromination of (Hetero)Aryl Boronic Pinacol Esters.

A copper-mediated radiobromination of (hetero)aryl boronic pinacol esters is described. Cyclotron-produced [76/77Br]bromide was isolated using an anion exchange cartridge, wherein the pre-equilibration and elution solutions played a critical role in downstream deboro-bromination. The bromination tolerates a broad range of functional groups, labeling molecules with ranging electronic and steric effects. Bologically active radiopharmaceuticals were synthesized, including two radiobrominated inhibitors of poly ADP ribose polymerase, a clinically relevant chemotherapeutic target for ovarian, breast, and prostate cancers.

Synthesis and Reactivity of α‐Cumyl Bromodifluoromethanesulfenate: Application to the Radiosynthesis of [18F]ArylSCF3

AbstractA highly reactive electrophilic bromodifluoromethylthiolating reagent, α‐cumyl bromodifluoro‐methanesulfenate 1, was prepared to allow for direct bromodifluoromethylthiolation of aryl boron reagents. This coupling reaction takes place under copper catalysis, and affords a large range of bromodifluoromethylthiolated arenes. These compounds are amenable to various transformations including halogen exchange with [18F]KF/K222 , a process giving access to [18F]arylSCF3 in two steps from the corresponding aryl boronic pinacol esters.

Synthesis and Reactivity of α-Cumyl Bromodifluoromethanesulfenate: Application to the Radiosynthesis of [18 F]ArylSCF3.

A highly reactive electrophilic bromodifluoromethylthiolating reagent, α-cumyl bromodifluoro-methanesulfenate 1, was prepared to allow for direct bromodifluoromethylthiolation of aryl boron reagents. This coupling reaction takes place under copper catalysis, and affords a large range of bromodifluoromethylthiolated arenes. These compounds are amenable to various transformations including halogen exchange with [18 F]KF/K222 , a process giving access to [18 F]arylSCF3 in two steps from the corresponding aryl boronic pinacol esters.

Direct synthesis of arylboronic pinacol esters from arylamines

A Sandmeyer-type transformation of converting aromatic amines into the corresponding arylboronic pinacol esters has been developed.

Suzuki–Miyaura monocouplings of p-dibromobiphenyl and substituted p-dibromo(penta- p-phenylenes)

The mono/bis ratio for the Suzuki–Miyaura cross coupling of p-dibromobiphenyl and p-dibromo(penta- p-phenylenes) with arylboronic acids and esters has been studied. The coupling reaction is demonstrated to be highly selective for monoarylation when the substrate is a p-dibromooligoarene, while selective biarylation is obtained for p-diiodoterphenyl. The mono/bis coupling-ratio for these compounds was highly sensitive to the nature of the halogen involved, however steric hindrance or electronic characteristics of the boronic derivative did not affect the selectivity of the reaction. The reaction yields observed were higher at room temperature and when arylboronic pinacol esters were used. These reactions also offer a useful method for the preparation of asymmetrically substituted terphenyls and hexa- p-phenylenes, giving good yields.