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. 2009 Nov 18;131(45):16525-8.
doi: 10.1021/ja906480w.

C-H bond functionalization via hydride transfer: direct coupling of unactivated alkynes and sp(3) C-H bonds catalyzed by platinum tetraiodide

Paul A Vadola  1 , Dalibor Sames
Affiliations

C-H bond functionalization via hydride transfer: direct coupling of unactivated alkynes and sp(3) C-H bonds catalyzed by platinum tetraiodide

Paul A Vadola et al. J Am Chem Soc. .

Abstract

We report a catalytic intramolecular coupling between terminal unactivated alkynes and sp(3) C-H bonds via through-space hydride transfer (HT-cyclization of alkynes). This method enables one-step preparation of complex heterocyclic compounds by alpha-alkenylation of readily available cyclic ethers and amines. We show that PtI(4) is an effective Lewis acid catalyst for the activation of terminal alkynes for hydride attack and subsequent C-C bond formation. In addition, we have shown that the activity of neutral platinum salts (PtX(n)) can be modulated by the halide ligands. This modulation in turn allows for fine-tuning of the platinum center reactivity to match the reactivity and stability of selected substrates and products.

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Figures

Figure 1
Figure 1
The Effect of Halide Ligand on the Catalyst Activity. Initial rates of product 2 formation are shown in the plot. The inset lists the yields of product 2 and remaining starting material 1. Reactions performed at 0.05 M in dry MeCN. Yields were determined by GC, employing tetrachlorobenzene as an internal standard. E = CO2Me.
Scheme 1
Scheme 1
The Platinum-Catalyzed Coupling of Unactivated Alkynes and sp3 C-H Bonds via the Through-Space Hydride Transfer
Scheme 2
Scheme 2
Cyclization of 2-Alkyl-1-ethynylbenzenes and Proposed Mechanistic Rationales
Scheme 3
Scheme 3
HT-Cyclization of Deuterium Labeled Compounds 21 and 23
Scheme 4
Scheme 4
Proposed Mechanisms for the Platinum-catalyzed HT-cyclization
See this image and copyright information in PMC

References

    1. Godula K, Sames D. Science. 2006;312:67. - PubMed
    1. DeBoef B, Pastine SJ, Sames D. J. Am. Chem. Soc. 2004;126:6556. - PubMed
    2. Chatani N, Asaumi T, Yorimitsu S, Ikeda T, Kakiuchi F, Murai S. J. Am. Chem. Soc. 2001;123:10935. - PubMed
    1. Pastine SJ, McQuaid KM, Sames D. J. Am. Chem. Soc. 2005;127:12180. - PubMed
    2. Pastine SJ, Sames D. Org. Lett. 2005;7:5429. - PubMed
    3. McQuaid KM, Sames D. J. Am. Chem. Soc. 2009;131:402. - PMC - PubMed
    4. McQuaid KM, Long JZ, Sames D. Org. Lett. 2009;11:2972. - PMC - PubMed

    1. For other recent developments in the area of HT-cyclization, see: Zhang C, Murarka S, Seidel D. J. Org. Chem. 2009;74:419. Ruble JC, Hurd AR, Johnson TA, Sherry DA, Barbachyn MR, Toogood PL, Bundy GL, Graber DR, Kamilar GM. J. Am. Chem. Soc. 2009;131:3991. Zhang C, De CK, Mal R, Seidel D. J. Am. Chem. Soc. 2008;130:416.

    1. Barluenga J, Mastral MF, Azna F, Valdés C. Angew. Chem. Int. Ed. 2008;47:6594. - PubMed
    2. Shikanai D, Murase H, Hata T, Urabe H. J. Am. Chem. Soc. 2009;131:3166. - PubMed

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