Palladium‐Catalyzed Direct Synthesis of Organoboronic Acids

Abstract

Diboronic acid in the spotlight: Molander et al. have developed an excellent method for the direct synthesis of aryl boronic acids from aryl chlorides (see scheme). In this palladium‐catalyzed procedure, diboronic acid, a notably underutilized reagent, was used as the boron source. The boronic acid products can be isolated from the procedure, or used in one‐pot reactions to give a wide range of boronates and biaryls.

Copper-catalyzed synthesis of allenylboronic acids. Access to sterically encumbered homopropargylic alcohols and amines by propargylboration

“…Copper-catalyzed transformation of propargylic carbonates under basic conditions was used for the borylation process. 9a – c Similar to the catalytic synthesis of allylboronic acids, we employed diboronic acid 12 ( 5a ) as the B(OH) 2 source ( Table 1 ). 10 a Application of the acid form 5a instead of B 2 pin 2 ( ref.…”

Selective Activation of Arylboronate or Aryne Reactivity as a Versatile Postfunctionalization Strategy

“…For example, the halogen groups of 7d, 7e, and 7j would make it difficult or impossible to introduce a B(pin) group by lithiation or by Pd-catalyzed reactions. 40 Similarly, products 7a and 7d-j contain various sterically accessible Ar-H positions, which would rule out their synthesis by final-stage Ir-catalyzed C-H borylation; the B(pin) group must be brought in from a previous step. The aryne-based postfunctionalization therefore presents a valuable new route to new arylboronates; it complements existing strategies and it offers the possibility of elaborating arylboronates with new functional groups.…”

Transition‐Metal‐Catalyzed Synthesis of Chiral Allylboronates†

“…In recent decades, transition‐metal catalyzed borylation reactions have been extensively studied, aiming at lower catalyst loading, better functional group tolerance and stereoselectivity, and milder reaction conditions. [ 2‐12 ] The most common methods include: 1) borylation of organic halides; [ 13‐18 ] 2) direct C—H borylation; [ 19‐23 ] 3) boryl addition to unsaturated organic compounds, such as alkenes, alkynes, allenes, [ 24‐35 ] aldehydes, ketones, [ 36 ] and α , β ‐unsaturated compounds. [ 37‐40 ] In fact, noncatalytic methodologies are an important complement and should not be ignored.…”