The functionalization of a cascade of C(sp(2))-H/C(sp(3))-H bonds: synthesis of fused dihydropyrazoles via visible-light photoredox catalysis.

The functionalization of a cascade of C(sp(2))-H/C(sp(3))-H bonds in aldehyde hydrazones with simple 2,2-dibromo-1,3-dicarbonyls was achieved via visible-light photoredox catalysis. This method, which involves free radical addition, polar crossover and 6π electrocyclic reaction, provides an efficient approach for the synthesis of complex fused dihydropyrazoles and related derivatives with moderate to good yields and excellent regioselectivity under mild reaction conditions.

[1]  H. Heimgartner,et al.  Intramolekulare 1,3‐dipolare Cycloadditionen mit alkenyl‐substituierten 3,4‐Diarylsydnonen , 1986 .

[2]  R. Grigg,et al.  A catalytic dehydrogenation route to azomethine imines. , 1990 .

[3]  G. Han,et al.  Exploratory Synthetic Studies of the α-Methoxylation of Amides via Cuprous Ion-Promoted Decomposition of o-Diazobenzamides† , 1996 .

[4]  A. G. Fallis,et al.  Free radical cyclizations involving nitrogen , 1997 .

[5]  G. Friestad.  Addition of carbon-centered radicals to imines and related compounds , 2001 .

[6]  The Daphniphyllum alkaloids. , 2009, The Alkaloids. Chemistry and biology.

[7]  Youwei Yan,et al.  Kinesin spindle protein (KSP) inhibitors. Part 7: Design and synthesis of 3,3-disubstituted dihydropyrazolobenzoxazines as potent inhibitors of the mitotic kinesin KSP. , 2007, Bioorganic & medicinal chemistry letters.

[8]  Ji-Young Kim,et al.  Synthesis and SAR of novel conformationally-restricted oxazolidinones possessing gram-positive and fastidious gram-negative antibacterial activity. Part 1: Substituted pyrazoles. , 2007, Bioorganic & medicinal chemistry letters.

[9]  K. Scheidt,et al.  Pyrrolidinyl-spirooxindole natural products as inspirations for the development of potential therapeutic agents. , 2007, Angewandte Chemie.

[10]  Pinaki S. Bhadury,et al.  Synthesis, structure and antibacterial activity of novel 1-(5-substituted-3-substituted-4,5-dihydropyrazol-1-yl)ethanone oxime ester derivatives. , 2008, Bioorganic & medicinal chemistry.

[11]  Riccardo Spinelli,et al.  Phase I pharmacokinetic and pharmacodynamic study of the aurora kinase inhibitor danusertib in patients with advanced or metastatic solid tumors. , 2009, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[12]  N. Gray,et al.  Targeting cancer with small molecule kinase inhibitors , 2009, Nature Reviews Cancer.

[13]  C. Stephenson,et al.  Visible-light photoredox catalysis: aza-Henry reactions via C-H functionalization. , 2010, Journal of the American Chemical Society.

[14]  Christopher K Prier,et al.  Discovery of an α-Amino C–H Arylation Reaction Using the Strategy of Accelerated Serendipity , 2011, Science.

[15]  W. Xiao,et al.  Visible-light-induced oxidation/[3+2] cycloaddition/oxidative aromatization sequence: a photocatalytic strategy to construct pyrrolo[2,1-a]isoquinolines. , 2011, Angewandte Chemie.

[16]  W. Xiao,et al.  Visible light-induced intramolecular cyclization reactions of diamines: a new strategy to construct tetrahydroimidazoles. , 2011, Chemical communications.

[17]  Corey R J Stephenson,et al.  Visible light photoredox catalysis: applications in organic synthesis. , 2011, Chemical Society reviews.

[18]  Qisong Liu,et al.  Visible-light-promoted C-C bond cleavage: photocatalytic generation of iminium ions and amino radicals. , 2012, Angewandte Chemie.

[19]  N. Chen,et al.  Lycojaponicumins A-C, three alkaloids with an unprecedented skeleton from Lycopodium japonicum. , 2012, Organic letters.

[20]  K. Takeda,et al.  Design , Synthesis , and Structure − Activity Relationships of Novel Pyrazolo [ 5 , 1 ‐ b ] thiazole Derivatives as Potent and Orally Active Corticotropin-Releasing Factor 1 Receptor Antagonists , 2012 .

[21]  D. Bouzida,et al.  Discovery of pyrroloaminopyrazoles as novel PAK inhibitors. , 2012, Journal of medicinal chemistry.

[22]  T. Rovis,et al.  Catalytic asymmetric α-acylation of tertiary amines mediated by a dual catalysis mode: N-heterocyclic carbene and photoredox catalysis. , 2012, Journal of the American Chemical Society.

[23]  Wen-Jing Xiao,et al.  Visible-light photoredox catalysis. , 2012, Angewandte Chemie.

[24]  Corey R J Stephenson,et al.  Functionally diverse nucleophilic trapping of iminium intermediates generated utilizing visible light. , 2012, Organic letters.

[25]  A. Lei,et al.  Synthetic applications of photoredox catalysis with visible light. , 2013, Organic & biomolecular chemistry.

[26]  Ruzhi Wang,et al.  Photodegradable supramolecular hydrogels with fluorescence turn-on reporter for photomodulation of cellular microenvironments. , 2013, Journal of the American Chemical Society.

[27]  N. Maulide,et al.  The redox-neutral approach to C-H functionalization. , 2013, Chemistry.

[28]  Axel G. Griesbeck,et al.  Photoredox Catalysis for Organic Syntheses , 2013 .

[29]  J. Xie,et al.  A visible-light-promoted aerobic C–H/C–N cleavage cascade to isoxazolidine skeletons , 2013 .

[30]  D. MacMillan,et al.  Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis. , 2013, Chemical reviews.

[31]  Jiang Wang,et al.  The chemistry of amine radical cations produced by visible light photoredox catalysis , 2013, Beilstein journal of organic chemistry.

[32]  P. Lu,et al.  Visible-light-mediated nucleophilic addition of an α-aminoalkyl radical to isocyanate or isothiocyanate. , 2013, Organic letters.

[33]  D. Seidel,et al.  C-H bond functionalization through intramolecular hydride transfer. , 2014, Angewandte Chemie.

[34]  Derek T. Ahneman,et al.  Merging photoredox with nickel catalysis: Coupling of α-carboxyl sp3-carbons with aryl halides , 2014, Science.

[35]  D. MacMillan,et al.  A general strategy for organocatalytic activation of C-H bonds via photoredox catalysis: direct arylation of benzylic ethers. , 2014, Journal of the American Chemical Society.

[36]  A. Goldman,et al.  Catalytic cleavage of ether C-O bonds by pincer iridium complexes. , 2014, Angewandte Chemie.

[37]  Liang Wang,et al.  Advancement in Cascade [1,n]-Hydrogen Transfer/Cyclization: A Method for Direct Functionalization of Inactive C(sp3)H Bonds , 2014 .

[38]  G. Molander,et al.  Single-electron transmetalation in organoboron cross-coupling by photoredox/nickel dual catalysis , 2014, Science.

[39]  Frank Glorius,et al.  Dual catalysis sees the light: combining photoredox with organo-, acid, and transition-metal catalysis. , 2014, Chemistry.

[40]  David A. Nicewicz,et al.  Recent Applications of Organic Dyes as Photoredox Catalysts in Organic Synthesis , 2014 .

[41]  J. T. Njardarson,et al.  Analysis of the structural diversity, substitution patterns, and frequency of nitrogen heterocycles among U.S. FDA approved pharmaceuticals. , 2014, Journal of medicinal chemistry.

[42]  Yixiang Cheng,et al.  Visible-light-induced direct C(sp3)-H difluromethylation of tetrahydroisoquinolines with the in situ generated difluoroenolates. , 2014, Chemical communications.

[43]  Pan Xu,et al.  When C-H bond functionalization meets visible-light photoredox catalysis , 2014 .

[44]  Danielle M. Schultz,et al.  Solar Synthesis: Prospects in Visible Light Photocatalysis , 2014, Science.

[45]  W. Xiao,et al.  Photocatalytic Generation of N-Centered Hydrazonyl Radicals: A Strategy for Hydroamination of β,γ-Unsaturated Hydrazones† , 2014 .

[46]  Yixiang Cheng,et al.  A novel visible light mediated radical cyclization of enol lactones: a concise method for fluorinated polycyclic lactone scaffolds. , 2015, Chemical communications.

[47]  W. Xiao,et al.  Photocatalytic Radical Trifluoromethylation/Cyclization Cascade: Synthesis of CF3-Containing Pyrazolines and Isoxazolines. , 2015, Organic letters.

[48]  Eric Meggers,et al.  Asymmetric catalysis activated by visible light. , 2015, Chemical communications.

[49]  Yixiang Cheng,et al.  Visible-Light-Induced Radical Tandem Aryldifluoroacetylation of Cinnamamides: Access to Difluoroacetylated Quinolone-2-ones And 1-Azaspiro[4.5]decanes , 2015 .

[50]  H. Alper,et al.  Redox-neutral α-allylation of amines by combining palladium catalysis and visible-light photoredox catalysis. , 2015, Angewandte Chemie.

[51]  J. Xie,et al.  Gold-Catalyzed Highly Selective Photoredox C(sp(2) )-H Difluoroalkylation and Perfluoroalkylation of Hydrazones. , 2016, Angewandte Chemie.

[52]  Shuhua Li,et al.  Visible-Light Photoredox-Catalyzed C-H Difluoroalkylation of Hydrazones through an Aminyl Radical/Polar Mechanism. , 2016, Angewandte Chemie.