Persistent P-Stabilized Boryl Radicals with Bulky Substituents at Boron

Amos J. Rosenthal; Sonia Mallet-Ladeira; Ghenwa Bouhadir; Didier Bourissou

doi:10.1055/s-0037-1610151

Synthesis, Table of Contents

Synthesis 2018; 50(18): 3671-3678
DOI: 10.1055/s-0037-1610151

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Persistent P-Stabilized Boryl Radicals with Bulky Substituents at Boron

Authors

Amos J. Rosenthal

^aCNRS, Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 route de Narbonne, 31062 Toulouse Cedex 09, France Email: dbouriss@chimie.ups-tlse.fr
Sonia Mallet-Ladeira

^bInstitut de Chimie de Toulouse (FR 2599), 118 route de Narbonne, 31062 Toulouse Cedex 9, France
Ghenwa Bouhadir

^aCNRS, Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 route de Narbonne, 31062 Toulouse Cedex 09, France Email: dbouriss@chimie.ups-tlse.fr
Didier Bourissou *

^aCNRS, Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 route de Narbonne, 31062 Toulouse Cedex 09, France Email: dbouriss@chimie.ups-tlse.fr

Abstract

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Published as part of the Special Section on the Main Group Metal Chemistry Symposium

Abstract

Two new P-stabilized boryl radicals [Ph₂P(naph)BAr] (Ar = Tip and Ter) have been prepared and characterized by electron paramagnetic resonance spectroscopy. These radicals are persistent for several days in solution at room temperature. The high steric congestion at boron does not prevent radical reactivity. Two different types of dimerization equilibrium have been observed. The structures of the dimers have been unambiguously established by X-ray diffraction crystallography.

Key words

radicals - boron - boryl radicals - phosphorus - Gomberg-type dimerization - m-terphenyl - EPR spectroscopy - X-ray diffraction

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References

References

1a Power PP. Chem. Rev. 2003; 103: 789
1b Chivers T. Konu J. In Comprehensive Inorganic Chemistry II: From Elements to Applications, Volume 1: Main-Group Elements, Including Noble Gases. Chivers T. Elsevier; Amsterdam: 2013: 349

2 Chiu CW. Gabbai FP. Angew. Chem. Int. Ed. 2007; 46: 1723

3a Ueng SH. Solovyev A. Yuan X. Geib SJ. Fensterbank L. Lacôte E. Malacria M. Newcomb M. Walton JC. Curran DP. J. Am. Chem. Soc. 2009; 131: 11256
3b Walton JC. Brahmi MM. Fensterbank L. Lacôte E. Malacria M. Chu Q. Ueng SH. Solovyev A. Curran DP. J. Am. Chem. Soc. 2010; 132: 2350
3c Matsumoto T. Gabbai FP. Organometallics 2009; 28: 4252
3d Martin CD. Soleilhavoup M. Bertrand G. Chem. Sci. 2013; 4: 3020
3e Bertermann R. Braunschweig H. Dewhurst RD. Hörl C. Kramer T. Krummenacher I. Angew. Chem. Int. Ed. 2014; 53: 5453
3f Silva Valverde MF. Schweyen P. Gisinger D. Bannenberg T. Freytag M. Kleeberg C. Tamm M. Angew. Chem. Int. Ed. 2017; 56: 1135

4a Ahcheh F. Martin D. Stephan DW. Bertrand G. Angew. Chem. Int. Ed. 2014; 53: 13159
4b Bissinger P. Braunschweig H. Damme A. Krummenacher I. Phukan AK. Radacki K. Sugawara S. Angew. Chem. Int. Ed. 2014; 53: 7360
4c Braunschweig H. Krummenacher I. Légaré MA. Matler A. Radacki K. Ye Q. J. Am. Chem. Soc. 2017; 139: 1802

5a Bontemps S. Devillard M. Mallet-Ladeira S. Bouhadir G. Miqueu K. Bourissou D. Inorg. Chem. 2013; 52: 4714
5b Devillard M. Brousses R. Miqueu K. Bouhadir G. Bourissou D. Angew. Chem. Int. Ed. 2015; 54: 5722
5c Devillard M. Bouhadir G. Mallet-Ladeira S. Miqueu K. Bourissou D. Organometallics 2016; 35: 3788

6a Rosenthal AJ. Devillard M. Miqueu K. Bouhadir G. Bourissou D. Angew. Chem. Int. Ed. 2015; 54: 9198
6b Rosenthal AJ. Mallet-Ladeira S. Bouhadir G. Sosa-Carrizo ED. Miqueu K. Bourissou D. Organometallics 2018; 37: 755

7 See the Supporting Information.

8a Clyburne JA. C. McMullen N. Coord. Chem. Rev. 2000; 210: 73
8b Rivard E. Power PP. Dalton Trans. 2008; 4336
8c Jutzi P. Angew. Chem. Int. Ed. 2011; 50: 9020

9 Couplings to ¹¹B do not exceed 8.5 G, even for NHC-stabilized boryl radicals which are considered among the leaders in terms of boron spin density; see ref. 3f.
10 Prohibitively long delays are needed to reach equilibration and accurately estimate the radical concentration.
11 Bond lengths of 1.55–1.59 Å were found in CHsp3–CHsp3 dimers of benzazaborolyl radicals; see: Hejda M. Lyčka A. Mikysek T. Jambor R. Růžička A. Vinklárek J. Wilfer C. Hoffmann A. Herres-Pawlis S. Dostál L. Chem. Eur. J. 2016; 22: 15340
12 Grimme S. Schreiner PR. Angew. Chem. Int. Ed. 2011; 50: 12639
13 Rösel S. Balestrieri C. Schreiner PR. Chem. Sci. 2017; 8: 405
14 Yu L. Li Y. Wang X. Wang X. Zhou P. Jiang S. Pan X. Chem. Commun. 2017; 53: 9737
15 Bartlett RA. Rasika Dias HV. Feng X. Power PP. J. Am. Chem. Soc. 1989; 111: 1306
16 Grigsby WJ. Power PP. J. Am. Chem. Soc. 1996; 118: 7981

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