Silylative Reductive Amination of α,β-Unsaturated Aldehydes: A Convenient Synthetic Route to β-Silylated Secondary Amines.

Described here is a reductive amination/hydrosilylation cascade of α,β-unsaturated aldehydes mediated by a Lewis acidic borane catalyst. The present reaction system provides an one-pot synthetic route towards β-silylated secondary amines that have not been accessible by other previous catalysis. Comparative 1 H NMR studies on the silylative reduction of enimines revealed that steric bulkiness of primary amine reactants strongly affects both catalytic efficiency and regioselectivity. This strategy was applicable to a broad range of substrates and amenable to one-pot gram-scale synthesis. Moreover, a diastereoselective introduction of the β-silyl group was also found to be feasible (d.r. up to 71:29).

[1]  B. E. Rossiter,et al.  asymmetric conjugate addition , 1992, Catalysis from A to Z.

[2]  Sukbok Chang,et al.  Boron-Catalyzed Hydrogenative Reduction of Substituted Quinolines to Tetrahydroquinolines with Hydrosilanes , 2017 .

[3]  Sukbok Chang,et al.  Borane catalysed ring opening and closing cascades of furans leading to silicon functionalized synthetic intermediates , 2016, Nature Communications.

[4]  V. Marcos,et al.  Old tricks, new dogs: organocatalytic dienamine activation of α,β-unsaturated aldehydes , 2016, Chemical Society reviews.

[5]  Sukbok Chang,et al.  Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact. , 2016, Angewandte Chemie.

[6]  Sukbok Chang,et al.  Selective Silylative Reduction of Pyridines Leading to Structurally Diverse Azacyclic Compounds with the Formation of sp³ C-Si Bonds. , 2015, Journal of the American Chemical Society.

[7]  Sukbok Chang,et al.  Boron-Catalyzed Silylative Reduction of Nitriles in Accessing Primary Amines and Imines. , 2015, The Journal of organic chemistry.

[8]  Sung-Woo Park,et al.  Chemoselective Silylative Reduction of Conjugated Nitriles under Metal-Free Catalytic Conditions: β-Silyl Amines and Enamines. , 2015, Angewandte Chemie.

[9]  Katherine M. Byrd Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams , 2015, Beilstein journal of organic chemistry.

[10]  M. Oestreich,et al.  A unified survey of Si-H and H-H bond activation catalysed by electron-deficient boranes. , 2015, Chemical Society reviews.

[11]  J. Djukic,et al.  Efficient hydrosilylation of imines using catalysts based on iridium(III) metallacycles , 2015 .

[12]  Sung-Woo Park,et al.  Boron-catalyzed silylative reduction of quinolines: selective sp3 C-Si bond formation. , 2014, Journal of the American Chemical Society.

[13]  W. Piers,et al.  Direct observation of a borane-silane complex involved in frustrated Lewis-pair-mediated hydrosilylations. , 2014, Nature chemistry.

[14]  A. Whiting,et al.  Understanding α,β-unsaturated imine formation from amine additions to α,β-unsaturated aldehydes and ketones: an analytical and theoretical investigation. , 2014, The Journal of organic chemistry.

[15]  M. Bao,et al.  Exclusive chemoselective reduction of imines in the coexistence of aldehydes using AuNPore catalyst. , 2014, Organic letters.

[16]  P. Melchiorre,et al.  Direct catalytic enantioselective vinylogous aldol reaction of α-branched enals with isatins. , 2012, Organic letters.

[17]  H. Pellissier Asymmetric Organocatalytic Cycloadditions , 2012 .

[18]  S. Tsuzuki,et al.  Organocatalytic, enantioselective intramolecular [6+2] cycloaddition reaction for the formation of tricyclopentanoids and insight on its mechanism from a computational study. , 2011, Journal of the American Chemical Society.

[19]  Ying‐Chun Chen,et al.  exo-Selective asymmetric Diels-Alder reaction of 2,4-dienals and nitroalkenes by trienamine catalysis. , 2011, Angewandte Chemie.

[20]  A. Moyano,et al.  Asymmetric organocatalytic cyclization and cycloaddition reactions. , 2011, Chemical reviews.

[21]  Masahiro Yoshida,et al.  Enantiocontrolled total syntheses of breviones A, B, and C. , 2011, Journal of the American Chemical Society.

[22]  P. Wipf,et al.  Total synthesis of (±)-cycloclavine and (±)-5-epi-cycloclavine. , 2011, Journal of the American Chemical Society.

[23]  K. Jørgensen,et al.  Trienamines in asymmetric organocatalysis: Diels-Alder and tandem reactions. , 2011, Journal of the American Chemical Society.

[24]  S. Herzon,et al.  11-Step enantioselective synthesis of (-)-lomaiviticin aglycon. , 2011, Journal of the American Chemical Society.

[25]  P. Melchiorre,et al.  Cooperative organocatalysis for the asymmetric γ alkylation of α-branched enals. , 2010, Angewandte Chemie.

[26]  A. Csákÿ,et al.  Conjugate addition reactions of carbon nucleophiles to electron-deficient dienes. , 2010, Chemical Society reviews.

[27]  A. Mazzanti,et al.  Direct asymmetric vinylogous Michael addition of cyclic enones to nitroalkenes via dienamine catalysis , 2010, Proceedings of the National Academy of Sciences.

[28]  Y. Mizobe,et al.  Heterolytic cleavage of hydrogen molecule by rhodium thiolate complexes that catalyze chemoselective hydrogenation of imines under ambient conditions. , 2009, Journal of the American Chemical Society.

[29]  Yugen Zhang,et al.  An efficient metal-free reduction using diphenylsilane with (tris–perfluorophenyl)borane as catalyst , 2009 .

[30]  K. Jiang,et al.  Organocatalytic regio- and stereoselective inverse-electron-demand aza-Diels-Alder reaction of alpha,beta-unsaturated aldehydes and N-tosyl-1-aza-1,3-butadienes. , 2009, Angewandte Chemie.

[31]  B. Feringa,et al.  Recent advances in enantioselective copper-catalyzed 1,4-addition. , 2009, Chemical Society reviews.

[32]  M. Shimizu,et al.  Conjugated imines and iminium salts as versatile acceptors of nucleophiles. , 2009, Chemical communications.

[33]  A. Alexakis,et al.  Enantioselective copper-catalyzed conjugate addition and allylic substitution reactions. , 2008, Chemical reviews.

[34]  J. Ellman,et al.  Synthesis of dihydropyridines and pyridines from imines and alkynes via C-H activation. , 2008, Journal of the American Chemical Society.

[35]  A. Córdova,et al.  Direct enantioselective synthesis of bicyclic Diels–Alder products , 2007 .

[36]  J. Vicario,et al.  Organocatalytic Enantioselective Michael and Hetero‐Michael Reactions , 2007 .

[37]  S. Tsogoeva Recent Advances in Asymmetric Organocatalytic 1,4‐Conjugate Additions , 2007 .

[38]  D. Alonso,et al.  Organocatalytic asymmetric conjugate additions , 2007 .

[39]  K. Jørgensen,et al.  Dienamine catalysis: organocatalytic asymmetric gamma-amination of alpha,beta-unsaturated aldehydes. , 2006, Journal of the American Chemical Society.

[40]  N. Turner,et al.  A chemo-enzymatic route to enantiomerically pure cyclic tertiary amines. , 2006, Journal of the American Chemical Society.

[41]  S. Sengupta,et al.  Organocopper Reagents: Substitution, Conjugate Addition, Carbo/Metallocupration, and Other Reactions , 2004 .

[42]  Shinya Sato,et al.  One-pot reductive amination of aldehydes and ketones with α-picoline-borane in methanol, in water, and in neat conditions , 2004 .

[43]  W. Piers,et al.  B(C6F5)3 catalyzed hydrosilation of enones and silyl enol ethers , 2002 .

[44]  R. McDonald,et al.  Solution and Solid-State Characteristics of Imine Adducts with Tris(pentafluorophenyl)borane , 2002 .

[45]  V. Gevorgyan,et al.  Highly efficient B(C(6)F(5))(3)-catalyzed hydrosilylation of olefins. , 2002, The Journal of organic chemistry.

[46]  Piers,et al.  B(C(6)F(5))(3)-Catalyzed hydrosilation of imines via silyliminium intermediates , 2000, Organic letters.

[47]  John J. M. Wiener,et al.  New Strategies for Organic Catalysis: The First Enantioselective Organocatalytic 1,3-Dipolar Cycloaddition , 2000 .

[48]  Piers,et al.  Studies on the mechanism of B(C(6)F(5))(3)-catalyzed hydrosilation of carbonyl functions , 2000, The Journal of organic chemistry.

[49]  D. MacMillan,et al.  New Strategies for Organic Catalysis: The First Highly Enantioselective Organocatalytic Diels−Alder Reaction , 2000 .

[50]  V. Tarasevich,et al.  Reductive amination of oxygen-containing organic compounds , 1999 .

[51]  W. Piers,et al.  Tris(pentafluorophenyl)boron-Catalyzed Hydrosilation of Aromatic Aldehydes, Ketones, and Esters , 1996 .

[52]  Tatsuo Tanaka,et al.  Silafunctional compounds in organic synthesis. Part 20. Hydrogen peroxide oxidation of the silicon-carbon bond in organoalkoxysilanes , 1983 .