Synlett 2014; 25(11): 1525-1528
DOI: 10.1055/s-0033-1339125
cluster
© Georg Thieme Verlag Stuttgart · New York

Steric Control of Geminal Lewis Pair Behavior: Frustration Induced Dyotropic Rearrangement

Éva Dorkó
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
,
Eszter Varga
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
,
Tamás Gáti
b  Servier Research Institute of Medicinal Chemistry, Záhony Street 7, 1031 Budapest, Hungary
,
Tamás Holczbauer
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
,
Imre Pápai
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
,
Hasan Mehdi
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
,
Tibor Soós*
a  Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute of Organic Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary   Email: soos.tibor@ttk.mta.hu
› Author Affiliations
Further Information

Publication History

Received: 18 March 2014

Accepted after revision: 22 April 2014

Publication Date:
06 June 2014 (online)


Abstract

A series of methylene-linked boron/nitrogen geminal Lewis pairs were synthesized and the impacts of sterical effect on their chemical behavior were systematically investigated. Increasing the steric demand around the boron atom is manifested first by an incremental change in the structure of the resulting dative adducts. Accordingly, in the case of phenyl substituents (Alk2NCH2BPh2), formation of head-to-tail dimers/oligomers was observed, while such an intermolecular association was avoided when o-tolyl moiety was introduced [Alk2NCH2B(o-Tol)2], affording only an intramolecular dative complex. Further increase of sterical hindrance to a point (i.e. using mesityl substituents), however, caused a radical change in the structure; a dyotropic rearrangement occurred. Thus, steric interference induced a rearrangement in the geminal pair to relieve or minimize the frustration strain.

Supporting Information

 
  • References and Notes

  • 1 Welch GC, San Juan RR, Masuda JD, Stephan DW. Science 2006; 314: 1124
    • 3a Theuergarten E, Schlüns D, Grunenberg J, Daniliuc CG, Jones PG, Tamm M. Chem. Commun. 2010; 46: 8561
    • 3b Chernichenko K, Nieger M, Leskelä M, Repo T. Dalton Trans. 2012; 41: 9029
    • 3c Holtrichter-Rößmann T, Rösener C, Hellmann J, Uhl W, Würthwein E.-U, Fröhlich R, Wibbeling B. Organometallics 2012; 31: 3272
    • 3d Zheng W, Pi C, Wu H. Organometallics 2012; 31: 4072
    • 3e Freitag S, Henning J, Schubert H, Wesemann L. Angew. Chem. Int. Ed. 2013; 52: 5640
    • 3f Stute A, Kehr G, Fröhlich R, Erker G. Chem. Commun. 2011; 47: 4288
    • 3g Rosorius C, Kehr G, Fröhlich R, Grimme S, Erker G. Organometallics 2011; 30: 4211
    • 3h Xu X, Kehr G, Daniliuc CG, Erker G. J. Am. Chem. Soc. 2013; 135: 6465
    • 3i Bertini F, Hoffmann F, Appelt C, Uhl W, Ehlers AW, Slootweg JC, Lammertsma K. Organometallics 2013; 32: 6764
    • 3j Bertini F, Lyaskovskyy V, Timmer BJ. J, de Kanter FJ. J, Lutz M, Ehlers AW, Slootweg JC, Lammertsma K. J. Am. Chem. Soc. 2012; 134: 201
  • 4 Zhao L, Lu G, Huang F, Wang Z.-X. Dalton Trans. 2012; 41: 4674
  • 5 Cox PJ, Doidge-Harrison SM. S. V, Howie RA, Nowell IW, Taylor OJ, Wardell JL. J. Chem. Soc., Perkin Trans. 1 1989; 2017
  • 6 In the present study, the DFT calculations were carried out using the ωB97X-D functional. The energy values reported in the paper correspond to solution-phase Gibbs free energies that are based on ωB97X-D/6-311++G(3df,3pd) electronic energies and all additional terms (thermal contributions and solvent effects) obtained at the ωB97X-D/6-311G(d,p) level. For further details, see Supporting Information.
  • 7 For a review on dyotropic reactions, see: Fernández I, Cossío FP, Sierra MA. Chem. Rev. 2009; 109: 6687

    • For a selection of recent theoretical mechanistic studies of dyotropic rearrangements, see:
    • 8a Davis RL, Leverett CA, Romo D, Tantillo DJ. J. Org. Chem. 2011; 76: 7167
    • 8b Leverett CA, Purohit VC, Johnson AG, Davis RL, Tantillo DJ, Romo D. J. Am. Chem. Soc. 2012; 134: 13348
    • 8c Fernández I, Bickelhaupt FM, Cossío FP. Chem. Eur. J. 2012; 18: 12395
    • 8d Gutierrez O, Tantillo DJ. J. Org. Chem. 2012; 77: 8845
  • 9 Short H…H bond distances measured in the equilibrium structure of III are clear indications of the internal strain (see Supporting Information).
  • 10 The computed free energy balance cannot be regarded as a very accurate prediction due to the inaccuracy of the present computational approach. The error bar on the relative Gibbs free energies reported in the present work is expected to be about 3–4 kcal/mol.