ORGANIC
LETTERS
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Vol. XX, No. XX
000–000
Ligand-Controlled, Norbornene-Mediated,
Regio- and Diastereoselective
Rhodium-Catalyzed Intramolecular
Alkene Hydrosilylation Reactions
Yuanda Hua, Hiep H. Nguyen, William R. Scaggs, and Junha Jeon*
Department of Chemistry and Biochemistry, University of Texas at Arlington,
Texas 76019, United States
Received May 23, 2013
ABSTRACT
Ligand-controlled, norbornene-mediated, regio- and diastereoselective rhodium-catalyzed intramolecular alkene hydrosilylation of homoallyl silyl
ethers (1) exploiting either BINAP or 1,6-bis(diphenylphosphino)hexane (dpph) has been developed. This method permits selective access to
either trans-oxasilacyclopentanes (trans-2) or oxasilacyclohexanes (3) at will. A substoichiometric amount of norbornene markedly increased
both yield and selectivity. A norbornene-mediated hydride shuttle process is discussed.
Transition-metal-catalyzed alkene hydrosilylation, a di-
rect conversion to alkylsilanes via addition of siliconꢀ
metal hydride across a CꢀC double bond, is one of the
most important homogeneous catalytic processes.1 For
decades, many powerful metal-catalyzed hydrosilylation
strategies have been developed for the synthesis of not only
biomedically significant molecules but also functional
materials.2 Research efforts have primarily focused on
enhancing or altering the reactivity as well as regio- and
stereoselectivity, which are facilitated through an intra-
molecular3 hydrosilylation approach.4,5 In particular,
several applications of 1,3-stereocontrolled olefin hydro-
silylative cyclization6 have been demonstrated for the
synthesis of a structurally complex polyketide.7 However,
most known hydrosilylation strategies utilizing Pt-, Ru-,
and Rh-based catalysts to date have been limited to mainly
provide thermodynamically driven 1,3-cis-selective hydro-
silylation products regardless of olefin geometry,4,6 leading
to 1,3-syn-diols after oxidative desilylation8 (Scheme 1,
top). To our knowledge, a widely applicable 1,3-trans-
selective, kinetic hydrosilylative cyclization strategy of
homoallyl silyl ethers 1 accessing trans-oxasilacyclo-
pentanes (trans-2) has not been accomplished,9 which in
turn hinders the selective synthesis of a 1,3-anti-diol scaf-
fold7 in biologically active complex molecules (Scheme 1,
middle). In addition, the study toward the synthesis of
(1) (a) Hiyama, T.; Kusumoto, T. In Comprehensive organic synthe-
sis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford, 1991; Vol. 8, pp
763ꢀ792. (b) Marciniec, B. In Hydrosilylation: A Comprehensive Review
on Recent Advances; Marciniec, B., Ed.; Springer: Berlin, 2009; Vol. 1, pp
3ꢀ51.
(2) Ojima, I. In The chemistry of organic silicon compounds; Patai, S.,
Rappoport, Z., Eds.; John Wiley: New York, 1989; Chapter 25.
(3) (a) Bols, M.; Skrydstrup, T. Chem. Rev. 1995, 95, 1253. (b)
Fensterbank, L.; Malacria, M.; Sieburth, S. M. Synthesis 1997, 813.
(4) (a) Tamao, K.; Nakajima, T.; Sumiya, R.; Arai, H.; Higuchi, N.;
Ito, Y. J. Am. Chem. Soc. 1986, 108, 6090. (b) Tamao, K.; Nakagawa, Y.;
Arai, H.; Higuchi, N.; Ito, Y. J. Am. Chem. Soc. 1988, 110, 3712. (c)
Uozumi, Y.; Hayashi, T. J. Am. Chem. Soc. 1991, 113, 9887. (d) Tamao,
K.; Nakagawa, Y.; Ito, Y. Organometallics 1993, 12, 2291.
(5) (a) For bissilylation reaction, see: Murakami, M.; Suginome, M.;
Fujimoto, K.; Nakamura, H.; Andersson, P. G.; Ito, Y. J. Am. Chem.
Soc. 1993, 115, 6487. (b) For silylformylation, see: Zacuto, M. J.;
Leighton, J. L. J. Am. Chem. Soc. 2000, 122, 8587. (c) For silaboration,
see: Ohmura, T.; Furukawa, H.; Suginome, M. J. Am. Chem. Soc. 2006,
128, 13366.
(6) (a) Denmark, S. E.; Forbes, D. C. Tetrahedron Lett. 1992, 33,
5037. (b) Hoveyda, A. H.; Hale, M. R. J. Org. Chem. 1992, 57, 1643. (c)
Young, D. G. J.; Hale, M. R.; Hoveyda, A. H. Tetrahedron Lett. 1996,
37, 827. (d) Li, F.; Roush, W. R. Org. Lett. 2009, 11, 2932.
€
(7) (a) Bode, S. E.; Wolberg, M.; Muller, M. Synthesis 2006, 557. (b)
Rychnovsky, S. D. Chem. Rev. 1995, 95, 2021.
(8) Jones, G. R.; Landais, Y. Tetrahedron 1996, 52, 7599.
(9) (a) 1,3-trans-Selectivity for trisubstituted allyl alcohols was
reported.4a (b) 1,3-trans-Selectivity in silaboration was reported.5c
r
10.1021/ol401464n
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