Jakub Szyling

Ionic liquid catalyzed α-selective hydroboration of alkynoate esters.

The commercially available and easy‐to‐handle manganese complexes Mn(CO)₅Br and Mn₂(CO)₁₀ effectively catalyze the hydroboration of ketones under mild conditions, yielding secondary alcohols after hydrolysis. These simple catalysts exhibit broad tolerance to different functional groups including esters, halides, and nitroarenes. Moreover, the reaction proceeds with high chemoselectivity toward CO bonds in the presence of esters, nitriles, nitro groups, or double CC bond. The proposed procedure enables fast, efficient synthesis of O‐borylated products, which are easily hydrolyzed in a one‐pot manner to various aryl and alkyl alcohols (even unsaturated ones) in excellent yields. Thus, the developed procedure compares favorably with other Mn catalytic systems, which require lengthy preparation, the application of structurally and electronically advanced ligands, and oxygen‐ and moisture‐free conditions.

The commercially available and easy to handle manganese complexes Mn(CO)5Br and Mn2(CO)10 were found to effectively catalyze the hydroboration of ketones under mild conditions providing after hydrolysis secondary alcohols. These simple catalysts showed great tolerance to different functional groups. Moreover, the reaction proceeded with high chemoselectivity toward C=O in the presence of ester, nitrile, nitro group, or double C=C bond. The proposed procedure enables fast and efficient synthesis of O-borylated products, which are easily hydrolyzed in one-pot manner to various aryl and alkyl alcohols (even unsaturated ones) with excellent yields. Therefore, the developed procedure is very competitive to other Mn catalytic systems, which required long preparation steps, application of structurally and electronically advanced ligands, and oxygen and moisture free conditions.

The organocatalytic activity of choline-based ionic liquids in the hydroboration of ketones, aldehydes and carboxylic acids with pinacolborane was investigated. The method employed was based on a simple, inexpensive, biobased, reusable and environmentally friendly [Cho][OAc] catalyst. Detailed studies on catalyst screening, the optimization of reaction conditions, and substrate scope were carried out. [Cho][OAc] showed excellent tolerance to various functional groups and chemoselectivity towards C=O hydroboration, which occurred under mild conditions. Furthermore, it was shown that the reaction can be carried out under repetitive batch modes, allowing effective catalyst recycling and improving process productivity.

Despite recent advancements in the development of catalytic Markovnikov-selective hydroboration of alkenes, the metal-free procedure has long remained an unsolved challenge. Here, we report an organocatalytic Markovnikov-selective hy-droboration of aryl alkenes using a commercially available quaternary ammonium catalyst. The method is operationally simple, scalable, and compatible with a wide variety of substrates and it can be successfully applied in the synthesis of active pharmaceutical ingredients (API) such as Chlorphenoxamine. Through in-depth experimental and DFT studies, we elucidate a nuanced understanding of the mechanism and regioselectivity of this reaction.

Straightforward access to enynyl pinacol boronates via a one-pot selective diboration/protodeboration strategy.

ILs organocatalyzed regioselective hydroboration of alkenes with HBpin provides anti-Markovnikov adducts with high yields and selectivity. The system allows catalyst recycling up to 30 runs. Transformations of alkylboronic esters are also included.

A straightforward, efficient, and selective method for the preparation of novel boryl-functionalized enynes or dienes via [Pt(PPh₃)₄]-catalyzed diboration of a broad spectrum of symmetrical and unsymmetrical 1,3-diynes was developed. The catalytic cycle of diboration was proposed on the basis of low-temperature ³¹P NMR studies. An alternative isolation method via product condensation on a cold finger was developed, which, in contrast to previous literature reports, eliminates the need for the additional transformation of rapidly decomposing enynyl pinacol boronates to more stable silica-based column chromatography derivatives during the separation step. To prove the efficiency of this simple catalytic protocol, bisboryl-functionalized enynes were synthesized in a gram scale and tested as useful building blocks in advanced organic transformations, such as hydrosilylation and Suzuki and sila-Sonogashira couplings. The presence of silyl, boryl, as well as other functions like halogen or alkoxy in their structures builds a new class of multifunctionalized enynes that might be modified in various chemical reactions.

This comprehensive review highlights the hydroelementation reactions of conjugated and separated diynes to various products including enynes, dienes, allenes, polymers or cyclic compounds, and their further transformation to valuable compounds.