Theoretical insight into the mechanism of gold(I)-catalyzed rearrangement of 2-propargyl 2H-azirines to pyridines.

The title reaction is investigated in detail theoretically using density functional theory. After 5-endo-dig cyclization by nucleophilic attack, five possible pathways are taken into account in this work: direct ring expansion followed or accompanied by proton-transfer (paths A and B, respectively), 1,3-cationic migration (path C), proton-transfer before ring expansion (path D), and processing via a gold-nitrene (path E). Results indicate that the reaction would undergo the favored sequential pathway (path A) rather than other pathways. Moreover, the concerted mechanism (path B), which is designed to account for the selectivity of product in the experiment, would be unlikely in the reaction. The selectivity of product could be explained by the hindrance of ligand (t-BuXPhos) and the stability of the carbocation. Moreover, the binding energy of product complexes could account for the observed reaction rate.

[1]  Junliang Zhang,et al.  Gold-catalyzed cyclopropanation reactions using a carbenoid precursor toolbox. , 2015, Chemical Society reviews.

[2]  Fan Wu,et al.  Cu-catalyzed ring opening reaction of 2H-azirines with terminal alkynes: an easy access to 3-alkynylated pyrroles. , 2014, Organic letters.

[3]  Yuanzhi Xia,et al.  Substrate-Dependent Mechanisms for the Gold(I)-Catalyzed Cycloisomerization of Silyl-Tethered Enynes: A Computational Study , 2014 .

[4]  Chengjian Zhu,et al.  Gold-catalyzed C(sp3)-H bond functionalization. , 2014, Chemical Society reviews.

[5]  Cheol‐Min Park,et al.  Transition-metal-free synthesis of substituted pyridines via ring expansion of 2-allyl-2H-azirines. , 2014, Organic letters.

[6]  Abigail G Doyle,et al.  The chemistry of transition metals with three-membered ring heterocycles. , 2014, Chemical reviews.

[7]  F. Gagosz,et al.  Gold-catalyzed synthesis of functionalized pyridines by using 2H-azirines as synthetic equivalents of alkenyl nitrenes. , 2014, Angewandte Chemie.

[8]  D. Yufit,et al.  Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems , 2014, Beilstein journal of organic chemistry.

[9]  F. Toste,et al.  Development of catalysts and ligands for enantioselective gold catalysis. , 2014, Accounts of chemical research.

[10]  Xiangying Tang,et al.  Gold-catalyzed tandem reactions of methylenecyclopropanes and vinylidenecyclopropanes. , 2014, Accounts of chemical research.

[11]  A. Fürstner.  From understanding to prediction: gold- and platinum-based π-acid catalysis for target oriented synthesis. , 2014, Accounts of chemical research.

[12]  B. Yan,et al.  A density functional theory study of the mechanism of isomerization of 2-aryl-2H-azirines to 2,3-disubstituted indoles by FeCl2 and Rh2(O2CCF3)4. , 2014, Dalton transactions.

[13]  L. Fensterbank,et al.  Molecular complexity from polyunsaturated substrates: the gold catalysis approach. , 2014, Accounts of chemical research.

[14]  S. Rampino,et al.  An ab Initio Benchmark and DFT Validation Study on Gold(I)-Catalyzed Hydroamination of Alkynes. , 2014, Journal of chemical theory and computation.

[15]  A. Hashmi.  Dual gold catalysis. , 2014, Accounts of chemical research.

[16]  Seunghoon Shin,et al.  Catalytic access to α-oxo gold carbenes by N-O bond oxidants. , 2014, Accounts of chemical research.

[17]  Yuxue Li,et al.  1,3-Cationic alkylidene migration of nonclassical carbocation: a density functional theory study on gold(I)-catalyzed cycloisomerization of 1,5-enynes containing cyclopropene moiety. , 2014, Journal of the American Chemical Society.

[18]  B. Alcaide,et al.  Gold-catalyzed cyclization reactions of allenol and alkynol derivatives. , 2014, Accounts of chemical research.

[19]  Liming Zhang.  A Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation , 2014, Accounts of chemical research.

[20]  B. Ault,et al.  Comparison of the photochemistry of 3-methyl-2-phenyl-2H-azirine and 2-methyl-3-phenyl-2H-azirine. , 2014, The Journal of organic chemistry.

[21]  Cheng-Hang Liu,et al.  Gold(I)-catalyzed endo-selective intramolecular α-alkenylation of β-yne-furans: synthesis of seven-membered-ring-fused furans and DFT calculations. , 2013, Angewandte Chemie.

[22]  A. Echavarren,et al.  Gold-Catalyzed Rearrangements and Beyond , 2013, Accounts of chemical research.

[23]  R. Fausto,et al.  Capture of an elusive nitrile ylide as an intermediate in isoxazole-oxazole photoisomerization. , 2013, The Journal of organic chemistry.

[24]  D. Yufit,et al.  Cu(II)-catalyzed domino reaction of 2H-azirines with diazotetramic and diazotetronic acids. Synthesis of 2-substituted 2H-1,2,3-triazoles. , 2013, Organic & biomolecular chemistry.

[25]  F. Palacios,et al.  The Neber approach to 2-(tetrazol-5-yl)-2H-azirines. , 2013, The Journal of organic chemistry.

[26]  A. Khlebnikov,et al.  Recent Advances in 2H-Azirine Chemistry , 2013 .

[27]  K. Okamoto,et al.  An unexpected disproportional reaction of 2H-azirines giving (1E,3Z)-2-aza-1,3-dienes and aromatic nitriles in the presence of nickel catalysts. , 2012, Chemical communications.

[28]  R. Fausto,et al.  The pyrolysis of isoxazole revisited: a new primary product and the pivotal role of the vinylnitrene. A low-temperature matrix isolation and computational study. , 2011, Journal of the American Chemical Society.

[29]  S. Shaik,et al.  Assessment of Theoretical Methods for Complexes of Gold(I) and Gold(III) with Unsaturated Aliphatic Hydrocarbon: Which Density Functional Should We Choose? , 2011, Journal of chemical theory and computation.

[30]  Stefan Grimme,et al.  Effect of the damping function in dispersion corrected density functional theory , 2011, J. Comput. Chem..

[31]  A. S. Dudnik,et al.  On the validity of Au-vinylidenes in the gold-catalyzed 1,2-migratory cycloisomerization of skipped propargylpyridines. , 2010, Organic letters.

[32]  J. Wang,et al.  Gold(I)-catalyzed cycloisomerization of enynes containing cyclopropenes. , 2010, Angewandte Chemie.

[33]  N. Zheng,et al.  Fe(II)-catalyzed amination of aromatic C-H bonds via ring opening of 2H-azirines: synthesis of 2,3-disubstituted indoles. , 2010, Organic letters.

[34]  M. Lautens,et al.  Exploiting the chemistry of strained rings: synthesis of indoles via domino reaction of aryl iodides with 2H-azirines. , 2010, Organic letters.

[35]  A. S. Dudnik,et al.  Computation-guided development of Au-catalyzed cycloisomerizations proceeding via 1,2-Si or 1,2-H migrations: regiodivergent synthesis of silylfurans. , 2010, Journal of the American Chemical Society.

[36]  S. Grimme,et al.  A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. , 2010, The Journal of chemical physics.

[37]  C. Nevado,et al.  Mechanistic insights in gold-stabilized nonclassical carbocations: gold-catalyzed rearrangement of 3-cyclopropyl propargylic acetates. , 2010, Journal of the American Chemical Society.

[38]  Pratibha Sharma,et al.  Theoretical evaluation of global and local electrophilicity patterns to characterize hetero-Diels-Alder cycloaddition of three-membered 2H-azirine ring system. , 2010, The journal of physical chemistry. A.

[39]  Zhidan Liang,et al.  Simple conversion of enamines to 2H-azirines and their rearrangements under thermal conditions. , 2009, Organic letters.

[40]  Xin Li,et al.  DFT study of the mechanisms of in water Au(I)-catalyzed tandem [3,3]-rearrangement/Nazarov reaction/[1,2]-hydrogen shift of enynyl acetates: a proton-transport catalysis strategy in the water-catalyzed [1,2]-hydrogen shift. , 2007, Journal of the American Chemical Society.

[41]  F. A. Davis,et al.  Asymmetric synthesis of 2H-azirine 3-carboxylates. , 2007, Organic letters.

[42]  S. Grimme.  Semiempirical hybrid density functional with perturbative second-order correlation. , 2006, The Journal of chemical physics.

[43]  F. Weigend,et al.  Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy. , 2005, Physical chemistry chemical physics : PCCP.

[44]  H. Inui,et al.  Photochemistry of 2-(1-naphthyl)-2H-azirines in matrixes and in solutions: wavelength-dependent C-C and C-N bond cleavage of the azirine ring. , 2005, Journal of the American Chemical Society.

[45]  V. Barone,et al.  Toward reliable density functional methods without adjustable parameters: The PBE0 model , 1999 .

[46]  Benedetta Mennucci,et al.  New applications of integral equations methods for solvation continuum models: ionic solutions and liquid crystals , 1998 .

[47]  Jacopo Tomasi,et al.  Evaluation of Solvent Effects in Isotropic and Anisotropic Dielectrics and in Ionic Solutions with a Unified Integral Equation Method: Theoretical Bases, Computational Implementation, and Numerical Applications , 1997 .

[48]  Jacopo Tomasi,et al.  A new integral equation formalism for the polarizable continuum model: Theoretical background and applications to isotropic and anisotropic dielectrics , 1997 .

[49]  H. Stoll,et al.  Energy-adjustedab initio pseudopotentials for the second and third row transition elements , 1990 .

[50]  L. Curtiss,et al.  Intermolecular interactions from a natural bond orbital, donor-acceptor viewpoint , 1988 .

[51]  K. Fukui.  The path of chemical reactions - the IRC approach , 1981 .

[52]  K. Hartung,et al.  Die stereoisomeren Formen des o-Nitrobenzyl-methyl-ketoxims , 1925 .

[53]  S. Nolan,et al.  Mechanism of the [(NHC)Au(I)]-catalyzed rearrangement of allylic acetates. A DFT study. , 2009, Organic letters.

[54]  S. Chiba,et al.  Rh(II)-catalyzed isomerization of 2-aryl-2H-azirines to 2,3-disubstituted indoles , 2007 .