Expanding the Limits of Organoboron Chemistry: Synthesis of Functionalized Arylboronates

Abstract

Biomass has the potential to serve as a sustainable source of energy and organic carbon for our industrialized society. The focus of this Review is to present an overview of chemical catalytic transformations of biomass‐derived oxygenated feedstocks (primarily sugars and sugar‐alcohols) in the liquid phase to value‐added chemicals and fuels, with specific examples emphasizing the development of catalytic processes based on an understanding of the fundamental reaction chemistry. The key reactions involved in the processing of biomass are hydrolysis, dehydration, isomerization, aldol condensation, reforming, hydrogenation, and oxidation. Further, it is discussed how ideas based on fundamental chemical and catalytic concepts lead to strategies for the control of reaction pathways and process conditions to produce H2/CO2 or H2/CO gas mixtures by aqueous‐phase reforming, to produce furan compounds by selective dehydration of carbohydrates, and to produce liquid alkanes by the combination of aldol condensation and dehydration/hydrogenation processes.

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

“…Given their utility in Suzuki–Miyaura cross-coupling reactions, the selective synthesis of aryl boronate esters is extremely important. − While borylations of C–H bonds with B 2 pin 2 has proven to be a valuable and widely used synthetic methodology, the reaction can suffer from poor regiocontrol. To overcome this issue there has been considerable interest in the boryl substitutions of other functional groups on an aromatic ring using B 2 pin 2 .…”

Palladium-catalyzed borylation of aryl (pseudo)halides and its applications in biaryl synthesis

“…They were widely used in C–C, C–O, C–N and C–S bond forming reactions [1, 2], which are essential for the construction of bioactive molecules and organic building blocks. In particular, functionalized arylboronic esters are highly valuable because they are more stable compared with arylboronic acids [3, 4]. The most common method for the synthesis of arylboronic esters is the reaction of trialkyl borates with aryllithium or Grignard reagents.…”

Palladium-Catalyzed Borylative Cyclizations of α-(2-Bromoaryl) Ketones to Form 1,2-Benzoxaborinines

“…In this study, we envisioned that palladium catalyzes the borylative cyclization of α-(2-bromoaryl) ketones with pre-installed substituents to provide the functionalized benzo­[ c ]­[1,2]­oxaborinin-1-ol products (Figure d). , A range of the starting materials is easily accessible by well-established protocols, such as α-arylation of carbonyl compounds and Friedel–Crafts acylation of 2-bromo­phenyl­acetyl chloride, and has been used in transition-metal-catalyzed intra­molecular cyclizations to afford benzofuran and indole …”