NHC-stabilized 1-hydro-1H-borole and its nondegenerate sigmatropic isomers.

Electrophilic quenching of a carbene-stabilized π-boryl anion with the Brønsted acid Et(3)NHCl provides a convenient synthetic route to the parent NHC-stabilized 1-hydroborole, which isomerizes to the corresponding 3-hydroborole via two successive nondegenerate [1,5]-sigmatropic hydrogen migrations. Molecular structures of both isomers have been determined by X-ray crystallography.

[1]  T. Kupfer,et al.  Synthesis and structure of a carbene-stabilized pi-boryl anion. , 2010, Angewandte Chemie.

[2]  H. Braunschweig,et al.  Platinum substituted boroles. , 2010, Chemical communications.

[3]  Rian D. Dewhurst,et al.  A trimetallic gold boride complex with a fluxional gold-boron bond. , 2009, Angewandte Chemie.

[4]  M. Yamashita,et al.  Group-4 transition-metal boryl complexes: syntheses, structures, boron-metal bonding properties, and application as a polymerization catalyst. , 2009, Journal of the American Chemical Society.

[5]  M. Yamashita,et al.  Chemistry of boryllithium: synthesis, structure, and reactivity. , 2008, Journal of the American Chemical Society.

[6]  T. Kupfer,et al.  Direct functionalization at the boron center of antiaromatic chloroborole. , 2008, Chemical Communications.

[7]  M. Yamashita,et al.  Syntheses, structures, and reactivities of borylcopper and -zinc compounds: 1,4-silaboration of an alpha,beta-unsaturated ketone to form a gamma-siloxyallylborane. , 2008, Angewandte Chemie.

[8]  Rian D. Dewhurst,et al.  A linear, anionic dimetalloborylene complex. , 2008, Angewandte Chemie.

[9]  M. Yamashita,et al.  Crystal Structure of Boryllithium with Two THF Molecules and DFT Analysis of Its Property as a Boryl Anion , 2008 .

[10]  A. Wakamiya,et al.  Synthesis and Structural Characterization of Pentaarylboroles and Their Dianions , 2008 .

[11]  T. Kupfer,et al.  Structural evidence for antiaromaticity in free boroles. , 2008, Angewandte Chemie.

[12]  A. Wakamiya,et al.  Kinetically stabilized dibenzoborole as an electron-accepting building unit. , 2008, Chemical communications.

[13]  H. Schaefer,et al.  A stable, neutral diborene containing a B=B double bond. , 2007, Journal of the American Chemical Society.

[14]  F. Gabbaï,et al.  Structural changes accompanying the stepwise population of a B-C pi bond. , 2007, Angewandte Chemie.

[15]  M. Yamashita,et al.  Boryl anion attacks transition-metal chlorides to form boryl complexes: syntheses, spectroscopic, and structural studies on group 11 borylmetal complexes. , 2007, Angewandte Chemie.

[16]  M. Yamashita,et al.  Synthesis, structure of borylmagnesium, and its reaction with benzaldehyde to form benzoylborane. , 2007, Journal of the American Chemical Society.

[17]  M. Yamashita,et al.  Boryllithium: Isolation, Characterization, and Reactivity as a Boryl Anion , 2006, Science.

[18]  S. Gwaltney,et al.  Excitation Spectra of Dibenzoborole Containing π-Electron Systems: Controlling the Electronic Spectra by Changing the pπ−π* Conjugation , 2006 .

[19]  J. Ko,et al.  The role of borole in a fully conjugated electron-rich system. , 2004, Chemical communications.

[20]  J. Hoefelmeyer,et al.  Reactivity of the dimesityl-1,8-naphthalenediylborate anion: isolation of the borataalkene isomer and synthesis of 1,8-diborylnaphthalenes. , 2004, Dalton transactions.

[21]  K. Tamao,et al.  Dibenzoborole-Containing π-Electron Systems: Remarkable Fluorescence Change Based on the “On/Off” Control of the pπ−π* Conjugation , 2002 .

[22]  A. Katritzky,et al.  To what extent can aromaticity be defined uniquely? , 2002, The Journal of organic chemistry.

[23]  D. Parks,et al.  Synthesis, Properties, and Hydroboration Activity of the Highly Electrophilic Borane Bis(pentafluorophenyl)borane, HB(C6F5)21 , 1998 .

[24]  U. Englert,et al.  Borabenzene Derivatives. 24.1 From Lithium 1-Methylboratabenzene to 2-Mono- and 2,2-Disubstituted 1-Methyl-1,2-dihydroborinines with Me3Si, Me3Ge, Me3Sn, and Me3Pb Substituents. Degenerate Sigmatropic Rearrangements with Exceptionally Low Barriers and the Structure of 2-(Me3Sn)C5H5BMe , 1997 .

[25]  P. Power,et al.  Isolation and Reduction of Sterically Encumbered Arylboron Dihalides: Novel Boranediyl Insertion into C−C σ-Bonds , 1996 .

[26]  D. Parks,et al.  Bis(pentafluorophenyl)borane: Synthesis, Properties, and Hydroboration Chemistry of a Highly Electrophilic Borane Reagent , 1995 .

[27]  Paul von Ragué Schleyer,et al.  Aromaticity and Antiaromaticity in Five‐Membered C4H4X Ring Systems: “Classical” and “Magnetic” Concepts May Not Be “Orthogonal” , 1995 .

[28]  R. Boese,et al.  Derivate des Imidazols, VI. Stabile Carben‐Borane , 1993 .

[29]  R. Rousseau,et al.  Evaluation of the aromaticity of borepin: synthesis and properties of 1-substituted borepins , 1993 .

[30]  T. Fehlner,et al.  Incorporation of a complexed hydridoaluminum (AlH) fragment into a metallacycle. Preparation and characterization of CpCoC4Ph4AlH.cntdot.NEt3 , 1991 .

[31]  R. Boese,et al.  A 1,2:2,1‐Bis(2‐silapropane‐1,3‐diyl)diborane(6): Stabilization Product of Bis(trisyl)diborane(2)? , 1990 .

[32]  T. Fehlner,et al.  Conversion of an unsaturated metallacycle into a carbon-rich nido-metallacarborane. The BH fragment as a cluster functional group , 1989 .

[33]  G. Herberich,et al.  Derivates of 1,2-diborabenzene: II. (1,2-Dibora-3,5-cyclohexadiene)metal complexes. Crystal structure of (C5Me5)Rh(C4H4B2Cl2) , 1988 .

[34]  P. Fagan,et al.  Synthesis of boroles and their use in low-temperature Diels−Alder reactions with unactivated alkenes , 1988 .

[35]  P. Power,et al.  Isolation and x-ray crystal structure of the boron methylidenide ion [Mes2BCH2]- (Mes = 2,4,6-Me3C6H2): a boron-carbon double bonded alkene analog , 1987 .

[36]  P. Power,et al.  X-ray crystal structure of the boron-stabilized carbanion [Li(12-crown-4)2][CH2C6H2(3,5-Me2)(4-B{2,4,6-Me3C6H2}2)].cntdot.Et2O: evidence for boron ylide character , 1986 .

[37]  G. E. Herberich,et al.  Derivate des borols , 1986 .

[38]  H. Bestmann,et al.  Umsetzung von Phosphoniumyliden mit Alkyldichlorboranen , 1986 .

[39]  J. E. Galle,et al.  Bora-aromatic systems. Part 8. The physical and chemical consequences of cyclic conjugation in boracyclopolyenes. The antiaromatic character of pentaarylboroles. , 1986, Journal of the American Chemical Society.

[40]  H. Reisenauer,et al.  Simply Substituted Boraethenes , 1985 .

[41]  T. Fehlner,et al.  Preparation of a carbon-rich metallacarborane from a metallacycle , 1983 .

[42]  G. Kramer,et al.  Addition compounds of alkali metal hydrides : XVIII. Reaction of trialkylboranes with t-butyllithium. A general, convenient method for the preparation of lithium trialkylborohydrides , 1980 .

[43]  H. Brown,et al.  Rapid reaction of trialkylboranes with lithium aluminum hydride in the presence of triethylenediamine. Facile and quantitative synthesis of lithium trialkylborohydrides including derivatives with exceptionally large steric requirements , 1979 .

[44]  J. Eisch,et al.  Synthesis of pentaphenylborole, a potentially antiaromatic system , 1969 .

[45]  U. Englert,et al.  Derivate des Borols, XVI Bis(borol)nickel‐Komplexe2) , 1991 .

[46]  R. Tuggle,et al.  Lithium dimesitylborohydride bis(dimethoxyethane). New crystalline reagent for stereoselective reduction of ketones , 1974 .