Visible-light-promoted alkylation of unsaturated MIDA boronates using Ru(bpy)3Cl2 as the photoredox catalyst

The development of a visible light-mediated atom transfer radical addition (ATRA) of perfluoroalkyl iodides to ethynyl-, vinyl- and allyl-MIDA boronates using the reductive and oxidative quenching of [Ru(bpy)₃]Cl₂ is described. Using an operationally simple and mild protocol, the corresponding MIDA boronates containing perfluoroalkyl groups were obtained in moderate to high yields. The structures of three products were confirmed by single crystal X-ray diffraction studies.     

Suzuki-Miyaura cross-coupling of alkenyl tosylates with alkenyl MIDA boronates

A practical procedure for the palladium-catalysed Suzuki-Miyaura coupling of various alkenyl tosylates with alkenyl MIDA boronates has been developed. Commercially available trans-bromo[N-succinimidyl-bis(triphenylphosphine)]palladium(II) [Pd(PPh₃)₂NBS] is an effective catalyst under the slow release conditions of MIDA boronates; with less activated alkenyl tosylates addition of the cheap, air-stable tricyclohexylphosphine tetrafluoroborate enhances reactivity.     

Cation exchange media provide a multi-stage,orthogonal catch and release method for MIDA boronates bearing basic centers

An operationally simple and rapid purification of MIDA boronates is described. This method allows separation of MIDA boronates containing basic centers from those that are neutral as well as separation from species that do not contain the MIDA moiety using a single “catch and release” purification medium. Application of this method to the purification of reductive amination products is described. It is hoped that this facile, rapid and conceptually new isolation will stimulate further investigation of other functionalized silica gel media for the isolation of MIDA boronate building blocks.     

Preparation of highly functionalized 1,5-disubstituted tetrazoles via palladium-catalyzed Suzuki coupling

The preparation of a range of 1,5-disubstituted tetrazoles has been achieved through palladium-catalyzed Suzuki coupling. Using appropriately substituted 5-p-toluenesulfonyltetrazoles as substrates (obtained by cycloaddition of a substituted azide with p-toluenesulfonyl cyanide), this methodology provides access to a variety of highly substituted tetrazoles that would be difficult to access otherwise. The procedure is compatible with functional groups commonly found in drug-like molecules, and has been used to generate a number of compounds of potential biological interest.     

The synthesis and application of fluorous boronates without perfluorinated solvents

The synthesis of a fluorous diol 4 bearing a perfluorodecyl chain was described. A series of boronic acid were attached to 4 by esterification. The purification of the products was fulfilled by facile filtration instead of expensive and environmental troublesome fluorous liquid-liquid extraction. The Suzuki cross-coupling reactions of the formed fluorous boronates 5 underwent smoothly and the fluorous diol 4 was recycled in good yields.     

A convenient synthesis of 4-aryl-1,8-naphthyridin-2(1H)-ones by the Suzuki coupling

4-Halo-1,8-naphthyridin-2(1H)-ones readily available from 2-chloronicotinic acid were subjected to the Suzuki coupling reaction with arylboronic acids to give a diversity of 4-aryl-1,8-naphthyridin-2(1H)-ones.     

Ethynyl MIDA boronate: a readily accessible and highly versatile building block for small molecule synthesis

Ethynyl N-methyliminodiacetic acid (MIDA) boronate is a very useful building block for small molecule synthesis. This compound can serve as both a bifunctional acetylene equivalent with the capacity for terminus-selective bis-functionalization and a versatile starting material for the preparation of a wide range of other MIDA boronate building blocks.     

Synthesis of substituted 2-phenylhistamines via a microwave promoted Suzuki coupling

Substitutions on the 2-position of the imidazole ring of histamine have proven useful in a number of biochemical settings. Current art for the synthesis of these constructs relies upon a cumbersome and low-yielding condensation reaction. Here-in we report a new procedure for the synthesis of a series of substituted 2-phenylhistamines utilizing a microwave-promoted Suzuki coupling.     

Suzuki coupling for protein modification

Suzuki-coupling, a representative cross-coupling reaction between small molecules, can proceed on a protein surface in aqueous solution under mild conditions. The modified protein produced by the coupling reaction maintained its native like structure and function. In addition, fluorescent dye appended-protein acts as a fluorescent biosensor.     

Pd/SiC催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应性能

以高比表面积碳化硅为载体,通过液相还原法制备出Pd/SiC催化剂,并用于催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应.利用X射线衍射、电感耦合等离子体质谱和高分辨透射电子显微镜等对催化剂进行了表征.结果表明, SiC表面的Pd纳米颗粒分散均匀,平均粒径约为2.8 nm.在优化溶剂、碱、压力和温度等反应条件后,发现以3 mmol的K2CO3和10 mL苯甲醚分别为碱和溶剂,1.0 mmol碘苯和1.5 mmol苯硼酸在3 wt% Pd/SiC催化剂存在的条件下,在CO压力为1.0 MPa和100oC下反应8 h即可实现羰化偶联,碘苯转化率为90%,二苯甲酮选择性为99%.并且, Pd/SiC对含有不同官能团的碘代芳烃和芳基硼酸羰化Suzuki偶联反应具有较好的普适性.同时, Pd/SiC也具有较好的稳定性,经5次循环反应后,碘苯转化率从90%降至76%;催化剂活性降低的主要原因是活性组分Pd在有机反应体系中的流失.     

功能化MCM-41负载双齿氮钯催化剂的制备及其在Suzuki偶联中的应用

首先胺功能化修饰介孔材料MCM-41,再与二-(吡啶-2-基-)甲酮缩合成席夫碱,最后通过Pd(OAc)2配位制备了MCM-41负载双齿氮钯配合物,采用X射线衍射(XRD)以及X射线光电子能谱(XPS)对其结构表征.该负载催化剂在以二甲苯为溶剂,K2CO3为碱以及n-Bu4NF用作添加剂的Suzuki偶联中表现出优越的催化性能.     

Pd/SiC催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应性能

以高比表面积碳化硅为载体,通过液相还原法制备出Pd/SiC催化剂,并用于催化碘代芳烃和芳基硼酸羰化Suzuki偶联反应.利用X射线衍射、电感耦合等离子体质谱和高分辨透射电子显微镜等对催化剂进行了表征.结果表明, SiC表面的Pd纳米颗粒分散均匀,平均粒径约为2.8 nm.在优化溶剂、碱、压力和温度等反应条件后,发现以3 mmol的K2CO3和10 mL苯甲醚分别为碱和溶剂,1.0 mmol碘苯和1.5 mmol苯硼酸在3 wt% Pd/SiC催化剂存在的条件下,在CO压力为1.0 MPa和100oC下反应8 h即可实现羰化偶联,碘苯转化率为90%,二苯甲酮选择性为99%.并且, Pd/SiC对含有不同官能团的碘代芳烃和芳基硼酸羰化Suzuki偶联反应具有较好的普适性.同时, Pd/SiC也具有较好的稳定性,经5次循环反应后,碘苯转化率从90%降至76%;催化剂活性降低的主要原因是活性组分Pd在有机反应体系中的流失.     

Tethered α-boryl radical cyclizations of haloalkyl boronates

Boroalkyl radicals readily cyclize onto alkenyl and alkynyl traps tethered via a C---B---O linkage. Oxidative cleavage of the C---B bond of the temporary connection following cyclization affords 1,3-diols in good yields.     

Nickel-promoted ligand-free palladium-catalyzed Suzuki coupling reaction

Summary A Ni-promoted ligand free palladium catalyst system for Suzuki coupling of aryl bromides has been developed in high efficiency under mild reaction conditions. It was obtained in situ by introducing NiCl₂ to PdCl₂/PVP using a parallel high-throughput screening technique. A wide range of aryl bromides bearing a variety of functional groups was evaluated.     

Palladium‐catalysed Suzuki cross‐coupling of primary alkylboronic acids with alkenyl halides

The Suzuki reaction of primary alkylboronic acids with alkenyl halides proceeds nicely using the air‐stable catalyst PdCl(C₃H₅)(dppb), Cs₂CO₃ as base and toluene or xylene as solvent. A minor effect of the substituent position of the alkenyl bromide was observed. Quite similar yields were observed in the presence of α‐ or β‐substituted alkenyl bromides such as 2‐bromobut‐1‐ene or 1‐bromo‐2‐methylprop‐1‐ene with this catalyst. This reaction proceeded with a variety of alkylboronic acids such as 2‐phenylethylboronic acid or n‐octylboronic acid. Lower yields of coupling products were obtained in the presence of an alkenyl chloride. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of 2-arylindoles by Suzuki coupling reaction of 3-bromoindoles with hindered benzoboronic acids

A new synthetic method for 2-arylindoles has been developed, the process through Suzuki coupling reaction of 3-bromoindoles with hindered boronic acid catalyzed by Pd(OAc)₂/PCy₃, and a series of 2-arylindoles have been synthesized in moderate to high yields.     

Efficient synthesis of isoflavone analogues via a Suzuki coupling reaction

Analogues of 3-aryl-8-isobutyl-5,6,7-trihydroxy-2-methyl-4H-chromen-4-one were synthesized with high yields via the Suzuki coupling reaction of 3-iodo-8-isobutyl-5,6,7-trimethoxy-2-methyl-4H-chromen-4-one with different aryl boronic acids.     

Heterogeneous Suzuki and Stille coupling reactions using highly efficient palladium(0) immobilized MCM-41 catalyst

An efficient palladium(0) immobilized MCM-41 catalytic system for C-C cross-coupling reaction has been developed. Ligand-free Pd(0)-MCM-41 catalyst can be successfully used in coupling reaction between various aryl halides including deactivated chlorobenzene with aryl borane and organotin to give biaryls in excellent yields with high turnover frequency (TOF) (the maximal TOFs are up to 6990 for the reaction of bromobenzene with phenylboronic acid). The catalyst can be recycled and reused without any loss of catalytic activity.     

Highly efficient photocatalytic Suzuki coupling reaction by Pd_3P/CdS catalyst under visible-light irradiation

Monodispersed palladium phosphide(Pd_3P)(5.2 ± 0.5 nm) was firstly applied to photocatalytic Suzuki coupling reaction under visible light irradiation with CdS nanoflake as a photo sensitizer.This heterogeneous system exhibited high yields to corresponding products and excellent stability in alcohol solvent at room temperature.