Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

• Jucleiton J. R. Freitas,
• Queila P. S. B. Freitas,
• Silvia R. C. P. Andrade,
• Juliano C. R. Freitas,
• Roberta A. Oliveira and
• Paulo H. Menezes

Beilstein J. Org. Chem. 2020, 16, 168–174, doi:10.3762/bjoc.16.19

• were obtained in short reaction time, high yield and purity without the need of any solvent when allenylboronic acid pinacol ester was used, or using a minimal amount of acetone when potassium allenyltrifluoroborate was used. Keywords: boron compounds; microwave; propargylation; regioselectivity

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• reaction could be a valuable approach to silicon rhodamines. Thus, we aimed at the optimization of coupling conditions as well as evaluation of the best boron compounds for coupling. Since carboxylic acid-substituted dyes like compound 17 (X = Si, R = COOH) can be easily coupled to tumor binding vectors

• , we wanted to investigate if these dyes are also accessible by Suzuki–Miyaura coupling. Results and Discussion Optimization of reaction conditions At first we investigated the effects of different catalysts and boron compounds on the synthesis of silicon rhodamine 22 via Suzuki–Miyaura cross coupling

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• utility is limited since it requires highly reactive boron compounds as nucleophiles. Symmetrical biphenyls 3’ can be generated from the corresponding symmetrically substituted diaryliodonium salts 1 and bis(pinacolato)diboron as demonstrated by Muñiz and co-workers [25]. In the first step, a mild carbon

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• -science [6][18][33][34][35][36][37][38], and material sciences [5][19][38][39] are emerging. Arylboronic acids and arylboronates represent versatile building blocks in organic synthesis [40]. They have found wide applications in transition metal-catalyzed cross-coupling reactions [41][42]. These boron

• compounds are accessed mainly by the reactions of arylmagnesium or aryllithium species with trialkylboronates [43][44], Pd- or Cu-catalyzed borylations of aryl halides using B2pin2, H-Bpin [45][46][47][48][49][50] or R2N-BH2 [51], direct borylations via aromatic C–H bond activations [52][53][54][55][56][57

Palladium-catalysed cross-coupling reaction of ultra-stabilised 2-aryl-1,3-dihydro-1H-benzo[d]1,3,2-diazaborole compounds with aryl bromides: A direct protocol for the preparation of unsymmetrical biaryls

• Siphamandla Sithebe and
• Ross S. Robinson

Beilstein J. Org. Chem. 2014, 10, 1107–1113, doi:10.3762/bjoc.10.109

• characteristics, fluoride ion sensing abilities, emissive as well as electron-transporting properties [8][9][10][11]. Three-coordinate boron compounds are electron-poor and strong π-electron acceptors owing to the empty boron pz-orbital, which is capable of significant delocalisation when attached to an organic π

• -coordinate boron compounds functionalized with 1,3,2-benzodiazaborole units are greatly stabilised by electron back-donation from the two nitrogen atoms to the empty boron pz-orbital (Figure 2, compound 6) [13][14]. Despite their popularity in the organic community, their profound stability towards air and

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• tools in synthetic organic chemistry. The most significant recent results and developments obtained in this area are reported in this review. Keywords: allylboration; boron compounds; Diels–Alder; 1,3-dienes; multicomponent reactions; Petasis borono–Mannich; Suzuki couplings; Introduction

• with high levels of atom economy. Boron compounds have long been ignored in this attractive area of research despite their wide range of reactivity [10][11]. In 1993, however, Petasis and co-workers reported a new synthesis of allylamines via stepwise condensation of a secondary amine, paraformaldehyde

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

• Tanveer Mahamadali Shaikh and
• Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

• . Therefore, the development of an alternative general and mild procedure employing a stable and inexpensive ligand is still in great demand. Furthermore, the application of palladium complexes in the oxidative coupling of organo-boron compounds with olefins has attracted much attention in recent years [33

Preparation and Diels–Alder/cross coupling reactions of a 2-diethanolaminoboron- substituted 1,3-diene

• Liqiong Wang,
• Cynthia S. Day,
• Marcus W. Wright and
• Mark E. Welker

Beilstein J. Org. Chem. 2009, 5, No. 45, doi:10.3762/bjoc.5.45

• :1. Elemental anal. calcd. for C13H22BNO4: C, 58.45; H, 8.30. Found: 58.17, 8.32. Representative Suzuki coupling procedure General procedure: Boron compounds and iodoaromatic compounds were added to a N2 flushed flask with Pd2(dba)3 and K2CO3 in acetonitrile and ethanol (30 mL). The mixture was