Doug Stephan

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FEATURE ARTICLE Zhiguang Guo et al. Recent progress of double-structural and functional materials... more FEATURE ARTICLE Zhiguang Guo et al. Recent progress of double-structural and functional materials with special wettability ... International Symposia on Advancing the Chemical Sciences (ISACS) ... Review current research developments and identify future challenges in a comprehensive plenary programme which explores the themes of Catalysis, Organometallic Chemistry, Porous Materials, Main Group Chemistry, Magnetism and Materials for Energy. ... Dynamic Hear from a new generation of exceptional, internationally renowned researchers who are all ...

Double Phosphinoboration of CO 2 : A Facile Route to Diphospha‐Ureas

Chemistry – A European Journal, 2019

The reactions of CO 2 with as eries of phosphinoboranes, including R 2 PBpin (R = Ph, tBu;p in = ... more The reactions of CO 2 with as eries of phosphinoboranes, including R 2 PBpin (R = Ph, tBu;p in = pinacol), R 2 PBMes 2 (R = Ph, tBu;M es = 2,4,6-Me 3-C 6 H 2), and R 2 PBcat (R = Ph, tBu, Mes;c at = catechol)a re described. Although R 2 PBpina nd R 2 PBMes 2 afford products of the form R 2 PCO 2 Bpin (R = Ph 1, tBu 4)a nd R 2 PCO 2 BMes 2 (R = Ph 2, tBu 3), respectively,R 2 PBcat lead to further reactionaffording the diphospha-ureas, (R 2 P) 2 CO (R = Ph 5, tBu 6,M es 7), together with O(Bcat) 2 .C omputational studiesp rovide insight into the mechanism, revealing an intermediate derived from double phosphinoboration of CO 2 .

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Titelbild: Heterolytic Dihydrogen Activation by a Frustrated Carbene-Borane Lewis Pair / Hydrogen and Amine Activation by a Frustrated Lewis Pair of a Bulky N-Heterocyclic Carbene and B(C 6 F 5 ) 3 (Angew. Chem. 39/2008)

Angewandte Chemie, 2008

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Titelbild: Metal-Free Catalytic Hydrogenation (Angew. Chem. 42/2007)

Angewandte Chemie, 2007

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Insertion reactions of the C–B–N-substituted borinium cation [MesBNiPr2]+

Dalton Transactions, 2020

The borinium cation [MesBNiPr2]+ reacts with isothiocyanate and carbodiimides affording a nitrili... more

Group 13-derived radicals from α-diimines via hydro- and carboalumination reactions

Dalton Transactions, 2020

Mechanochemically synthesized alanes and (hydrido-)alanes were reacted with α-diimines to form al... more

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The phosphinoboration of acyl chlorides

Dalton Transactions, 2020

This investigation examines the reactivity of phosphinoboronate esters Ph2PBpin (pin = 1,2-O2C2Me... more

Frustrated Lewis pair-catalyzed double hydroarylation of alkynes with N-substituted pyrroles

Chemical Communications, 2020

Metal-free hydroarylation of alkynes with N-substituted pyrroles is shown to be efficiently media... more

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9-Borabicyclo[3.3.l]nonane-induced Friedel–Crafts benzylation of arenes with benzyl fluorides

Organic & Biomolecular Chemistry, 2019

9-Borabicyclo[3.3.l]nonane dimer (9-BBN) mediates the Friedel–Crafts benzylation of arenes with b... more

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Hydroboration without a B–H bond: reactions of the borinium cation [(iPr2N)2B]+ with alkyne, nitrile, ketone and diazomethane

Chemical Communications, 2019

The borinium cation [(iPr2N)2B]+ (1+) is shown to react with PhCCH, PhCN, Ph2CO, and Ph2CN2 to ef... more

FLP reduction and hydroboration of phenanthrene o-iminoquinones and α-diimines

Dalton Transactions, 2017

Hydrogenation and hydroboration of an N-aryl-phenanthrene-o-iminoquinone and two N,N′-diaryl-phen... more

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Interactions of C−F Bonds with Hydridoboranes: Reduction, Borylation and Friedel-Crafts Alkylation

Chemistry - A European Journal, 2018

The stoichiometric reactions of the alkylfluorides 1fluoroadamantane (Ad-F), fluorocyclohexane (C... more The stoichiometric reactions of the alkylfluorides 1fluoroadamantane (Ad-F), fluorocyclohexane (Cy-F), 1fluoropentane (Pent-F) and benzyl fluorides with secondary boranes pinacolborane (HBpin), catecholborane (HBcat), 9borabicyclo(3.3.1)nonane (9-BBN) and Pier's borane (HB(C6F5)2) are described. While HBcat, 9-BBN and HB(C6F5)2 reduce Ad-F to Ad-H, the latter borane was shown to react with secondary and primary fluoroalkanes, affording C-F borylation, while benzyl fluorides undergo Friedel-Crafts chemistry.

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Activation of H2 and Et3SiH by the Borinium Cation [Mes2B]+: Avenues to Cations [MesB(μ-H)2(μ-Mes)BMes]+ and [H2B(μ-H)(μ-Mes)B(μ-Mes)(μ-H)BH2]+

Journal of the American Chemical Society, 2019

Reaction of dihydrogen and the borinium cation [Mes 2 B][B(C 6 F 5) 4 ] gave an arene-stabilized ... more Reaction of dihydrogen and the borinium cation [Mes 2 B][B(C 6 F 5) 4 ] gave an arene-stabilized mesityl-borenium cation, which isotopically scrambles HD. Similarly reaction with triethylsilane gave the diboranium cation, [MesB(-H) 2 (-Mes)BMes] + featuring three bridge-bonds between two boron centres. Reaction of [Mes 2 B][B(C 6 F 5) 4 ] with Brønsted acid also afforded the diboranium whereas the corresponding reaction with (MesBH 2) 2 yielded the triboron cation [H 2 B(-H)(-Mes)B(-Mes)(-H)BH 2 ] + .

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Reactions of B 2 ( o ‐tolyl) 4 with Boranes: Assembly of the Pentaborane(9), HB[B( o ‐tolyl)(μ‐H)] 4

Angewandte Chemie International Edition, 2021

Reactions of the diborane(4) B 2 (o-tolyl) 4 and monohydridoboranes are shown to give B(o-tolyl) ... more Reactions of the diborane(4) B 2 (o-tolyl) 4 and monohydridoboranes are shown to give B(o-tolyl) 3 and (otolyl)BR 2 (R 2 = (C 8 H 14) 3, cat 4, pin 5, (C 6 F 5) 2 6) as the major products. The corresponding reaction with BH 3-sources gives complex mixtures, resulting from hydride/aryl exchange, dimerization and borane elimination. This led to the isolation of the first tetra-substituted pentaborane(9) HB[B(o-tolyl)(m-H)] 4 8. The reaction pathways are probed experimentally and by computations.

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Cover Picture: Metal-Free Catalytic Hydrogenation (Angew. Chem. Int. Ed. 42/2007)

Angewandte Chemie International Edition, 2007

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Insertion reactions of the C–B–N-substituted borinium cation [MesBNiPr2]+

Dalton Transactions, 2020

The synthesis and isolation of the first stable C-B-N-substituted borinium [MesBNiPr2][B(C6F5)4] ... more The synthesis and isolation of the first stable C-B-N-substituted borinium [MesBNiPr2][B(C6F5)4] (2) is described. Compound 2 was shown to react with isothiocyanate and carbodiimides, effecting B–C insertion to afford nitrilium (4) and borenium amidinate salts, respectively. The borinium cation [MesBNiPr2]+ (2+) was also generated from reactions of MesB(Cl)NiPr2 (1) and GaCl3, and used to prepare stable borenium amidinate salts (5-6), while the triflate borane MesB(OTf)NiPr2 (7) reacts with carbodiimide to give the bis(amidinate) boronium salt [MesC(NiPr)2B((NiPr)2C)NiPr2][OTf] (8).

Lewis acid-catalyzed hydrogenation: B(C6F5)3-mediated reduction of imines and nitriles with H2

Chemical Communications

The Lewis acid B(C(6)F(5))(3) has been found to be an efficient catalyst for the direct hydrogena... more

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Metal-Free Catalytic Hydrogenation

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Double Phosphinoboration of CO2 : A Facile Route to Diphospha-Ureas

Chemistry - A European Journal, Jul 29, 2019

The reactions of CO2 with a series of phosphinoboranes, including R2PBpin (R = Ph, tBu), R2PBMes2... more The reactions of CO2 with a series of phosphinoboranes, including R2PBpin (R = Ph, tBu), R2PBMes2 (R = Ph, tBu), and R2PBcat (R = Ph, tBu, Mes) are described. While R2PBpin and R2PBMes2 afford products of the form R2PCO2Bpin (R = Ph 1, tBu 4) and R2PCO2BMes2 (R = Ph 2, tBu 3), respectively, R2PBcat lead to further reaction affording the diphospha‐ureas, (R2P)2CO (R = Ph 5, tBu 6, Mes 7), together with O(Bcat)2. Computational studies provide insight into the mechanism, revealing an intermediate derived from double phosphinoboration of CO2.

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Frustrated Lewis Pairs

Israel Journal of Chemistry, 2015

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