Mechanochemical borylation of aryldiazonium salts; merging light and ball milling

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1463–1469, doi:10.3762/bjoc.13.144

• . Simultaneous neat grinding/irradiation of the reactants and the photocatalyst led to the formation of boronates in a molten state. On the other hand, the catalyst-free liquid-assisted grinding/irradiation reaction also led to product formation, featuring a direct photolysis pathway facilitated by substrate

• ). With the optimized reaction conditions in hand, we explored the photomechanochemical borylation of the halogenated aryldiazonium salts 1a–d (Table 2). Analogously to the case of 1a, the fluoro and chloro substituted aryldiazonium salts 1b and 1c did react affording the boronates 3b and 3c (Table 2

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• sequence starts with the reaction of diazo compound 20, generated under flow conditions, and boronic acid 19 (Scheme 19). Further sequential coupling with diazo compounds 21 and 22 led to boronates 23 or protodeboronated products 24 at the end of the sequence (Scheme 19). With the aim to exploit the

(Z)-Selective Takai olefination of salicylaldehydes

• Stephen M. Geddis,
• Caroline E. Hagerman,
• Warren R. J. D. Galloway,
• Hannah F. Sore,
• Jonathan M. Goodman and
• David R. Spring

Beilstein J. Org. Chem. 2017, 13, 323–328, doi:10.3762/bjoc.13.35

• to generate vinyl stannanes [3], silanes [4] and boronates [5]. One of the most significant features of the Takai olefination is that it is generally highly selective for the formation of (E)-alkenes ((E):(Z)-product ratios are typically around 4:1 or greater). This selectivity has found wide use

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

• Arne Klinkebiel,
• Ole Beyer,
• Barbara Malawko and
• Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

• 5c. The resulting triazines 3b and 3c can then be coupled to boronic acids or boronates to give substituted and elongated triazine-based linkers. Furthermore, the reduction of the nitro group or cleavage of the methoxy group will give additional substituted linkers, amino and hydroxy-substituted ones

Spiro-fused carbohydrate oxazoline ligands: Synthesis and application as enantio-discrimination agents in asymmetric allylic alkylation

• Jochen Kraft,
• Martin Golkowski and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 166–171, doi:10.3762/bjoc.12.18

• ester 11 as boron source (Scheme 2) [22][23][24]. 2-Pyridineboronic acid 11 was chosen due to its increased nucleophilicity compared to other boron sources like pinacol boronic esters or MIDA boronates [25][26]. The cross coupling proceeded smoothly in THF and gave ligands 9 and 10 in good yields

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• example, disulfide [10], acetal [11], imine [12] and boronates [13][14][15][16], to allow the generation of new covalent structures under thermodynamic control. Complete esterification is observed for boronate esters bearing ortho-amines [17]. The conceptual advantage compared to traditional irreversible

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

• [72]. Straightforward access to SF5-phenylboronic acids or boronates would be highly desirable since it would allow easy installation of the SF5-phenyl group by the subsequent Suzuki–Miyaura reaction. Nitro-(pentafluorosulfanyl)benzenes are the primary industrial SF5-aromatics, therefore the easiest

• . Starting from aniline derivative 1b, a one pot diazotization–borylation sequence using different acids afforded the corresponding borylated product 2b in good yields (Table 3). Suzuki–Miyaura cross-coupling reactions of boronates 2a and 2b with aryl iodides using a simple system without any optimization

• proceeded in satisfactory yields considering the electron-deficient character of the boronates and consequently less efficient transmetallation step (Scheme 4). Transformation to SF5-phenylboronic acid 8b and potassium trifluoroborates 9 was straightforward under standard conditions (Scheme 5). Similar

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

• reaction conditions for the purpose of this study. With the optimized reaction conditions in hand, the scope and the limitations of the cross-coupling reaction was investigated using bromobenzene (13a) and 4-bromoanisole (13b) as elelctrophilic coupling partners and boronates 9–12 (Scheme 1) as the

• corresponding nucleophilic coupling partners (Table 2). The cross-coupling reaction of bromobenzene (13a) with boronates 9–12 went smooth affording the coupled products in yields ranging from 68% to 88% (Table 2, entries 1, 3, 5 and 7). The sterically hindered ortho-substituted boronate 11 generally afforded

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

• -phenylmaleimide and 4-phenyltriazoline-3,5-dione. Asymmetric synthesis of a α-hydroxyalkylcyclohexane. Tandem [4 + 2]-cycloaddition/allylboration of 3-silyloxy- and 4-alkoxy-dienyl boronates. Metal-mediated cycloisomerization/Diels–Alder reaction/allylboration sequence. Cobalt-catalyzed Diels–Alder/allylboration

Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• envisaged to be constructed by 1,2-addition, using the free β-hydroxy functionality in 63 as directing group. Several conditions with allyl boronates, stannanes, silanes, indium, magnesium bromide, cerium, zinc bromide and other reagents have been screened. Finally, the best result was achieved with

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Highly enantioselective access to cannabinoid-type tricyles by organocatalytic Diels–Alder reactions

• Stefan Bräse,
• Nicole Volz,
• Franziska Gläser and
• Martin Nieger

Beilstein J. Org. Chem. 2012, 8, 1385–1392, doi:10.3762/bjoc.8.160

• former experiments of our group [29][30][31] it became apparent that without a catalyst no conversion towards the desired product occurred. Only the homodimer of the diene 10 could be isolated. Metal-based Lewis acids (e.g., catechol boronates) proved to be inefficient or too reactive. Due to the fact

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• gold(I) complexes generated from a mixture of gold and silver salts [111]. Both, alkynyl and alkenyl pinacol boronates were tolerated. The ratio of the different endo- and exo-products was heavily dependent on the position of the boronate functionality (Scheme 42). Li et al. reported a gold-catalyzed

Stereogenic boron in 2-amino-1,1-diphenylethanol-based boronate–imine and amine complexes

• Sebastian Schlecht,
• Walter Frank and
• Manfred Braun

Beilstein J. Org. Chem. 2011, 7, 615–621, doi:10.3762/bjoc.7.72

• character (THC) of boronates 8 and 10. Summary of crystal data, details of intensity measurements and structure refinements of 8 and 10·CH3OH. Acknowledgements This work was supported by the Deutsche Forschungsgemeinschaft (Br 604/15-1,2).