ChemInform Abstract: Synthesis of Pyridines from Ketoximes and Terminal Alkynes via C-H Bond Functionalization.

ChemInform ◽  
2012 ◽  
Vol 43 (27) ◽  
pp. no-no
Author(s):  
Rhia M. Martin ◽  
Robert G. Bergman ◽  
Jonathan A. Ellman
Keyword(s):  
Terminal Alkynes ◽  
Bond Functionalization

scholarly journals Synthesis of Pyridines from Ketoximes and Terminal Alkynes via C–H Bond Functionalization

2012 ◽  
Vol 77 (5) ◽  
pp. 2501-2507 ◽  
Author(s):  
Rhia M. Martin ◽  
Robert G. Bergman ◽  
Jonathan A. Ellman
Keyword(s):  
Terminal Alkynes ◽  
Bond Functionalization

Regio- and stereo-selective decarbonylative alkylative arylation of terminal alkynes with aliphatic aldehydes and arenes via dual C–H bond functionalization

2019 ◽  
Vol 6 (20) ◽  
pp. 3597-3602
Author(s):  
Yong Peng ◽  
Feng Zhang ◽  
Ting-Ting Qin ◽  
Cong-Ling Xu ◽  
Luo Yang
Keyword(s):  
Terminal Alkynes ◽  
Aliphatic Aldehydes ◽  
Bond Functionalization ◽  
Alkyl Radicals ◽  
Sugar Derivatives

Readily available linear/branched aliphatic aldehydes including sugar derivatives were oxidatively decarbonylated into 1˙, 2˙ and 3˙ alkyl radicals for the alkylative arylation of terminal alkynes via dual C–H bond functionalization.

Fe-Promoted Chlorobenzylation of Terminal Alkynes through Benzylic C(sp3)–H Bond Functionalization

2016 ◽  
Vol 18 (6) ◽  
pp. 1238-1241 ◽  
Author(s):  
Jiang-Ling Shi ◽  
Ji-Cheng Zhang ◽  
Bi-Qin Wang ◽  
Ping Hu ◽  
Ke-Qing Zhao ◽  
...  
Keyword(s):  
Terminal Alkynes ◽  
Bond Functionalization

Silver-catalyzed direct selenylation of terminal alkynes through C H bond functionalization

2017 ◽  
Vol 427 ◽  
pp. 73-79 ◽  
Author(s):  
Maurício C.D.F. Xavier ◽  
Bruna Goldani ◽  
Ricardo F. Schumacher ◽  
Gelson Perin ◽  
Paulo Henrique Schneider ◽  
...  
Keyword(s):  
Terminal Alkynes ◽  
Bond Functionalization

ChemInform Abstract: Fe-Promoted Chlorobenzylation of Terminal Alkynes Through Benzylic C(sp3)-H Bond Functionalization.

ChemInform ◽  
2016 ◽  
Vol 47 (31) ◽  
Author(s):  
Jiang-Ling Shi ◽  
Ji-Cheng Zhang ◽  
Bi-Qin Wang ◽  
Ping Hu ◽  
Ke-Qing Zhao ◽  
...  
Keyword(s):  
Terminal Alkynes ◽  
Bond Functionalization

scholarly journals Copper-catalyzed enantioselective Sonogashira-type oxidative cross-coupling of unactivated C(sp3)−H bonds with alkynes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhen-Hua Zhang ◽  
Xiao-Yang Dong ◽  
Xuan-Yi Du ◽  
Qiang-Shuai Gu ◽  
Zhong-Liang Li ◽  
...  
Keyword(s):  
Transition Metal ◽  
Alkyl Radical ◽  
Cross Coupling ◽  
Cinchona Alkaloid ◽  
Terminal Alkynes ◽  
Radical Species ◽  
Bond Functionalization ◽  
Versatile Tool ◽  
Metal Catalyzed

AbstractTransition metal-catalyzed enantioselective Sonogashira-type oxidative C(sp3)—C(sp) coupling of unactivated C(sp3)−H bonds with terminal alkynes has remained a prominent challenge. The difficulties mainly stem from the regiocontrol in unactivated C(sp3)—H bond functionalization and the inhibition of readily occurring Glaser homocoupling of terminal alkynes. Here, we report a copper/chiral cinchona alkaloid-based N,N,P-ligand catalyst for asymmetric oxidative cross-coupling of unactivated C(sp3)—H bonds with terminal alkynes in a highly regio-, chemo-, and enantioselective manner. The use of N-fluoroamide as a mild oxidant is essential to site-selectively generate alkyl radical species while efficiently avoiding Glaser homocoupling. This reaction accommodates a range of (hetero)aryl and alkyl alkynes; (hetero)benzylic and propargylic C(sp3)−H bonds are all applicable. This process allows expedient access to chiral alkynyl amides/aldehydes. More importantly, it also provides a versatile tool for the construction of chiral C(sp3)—C(sp), C(sp3)—C(sp2), and C(sp3)—C(sp3) bonds when allied with follow-up transformations.

Molecular Basis of Iterative C–H Oxidation by TamI, a Multifunctional P450 Monooxygenase from the Tirandamycin Biosynthetic Pathway

2020 ◽  
Author(s):  
Sean A. Newmister ◽  
Kinshuk Raj Srivastava ◽  
Rosa V. Espinoza ◽  
Kersti Caddell Haatveit ◽  
Yogan Khatri ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Basis ◽  
Hydrophobic Interactions ◽  
Cytochromes P450 ◽  
Targeted Mutagenesis ◽  
P450 Monooxygenase ◽  
Bond Functionalization ◽  
Dynamics Simulations

Biocatalysis offers an expanding and powerful strategy to construct and diversify complex molecules by C-H bond functionalization. Due to their high selectivity, enzymes have become an essential tool for C-H bond functionalization and offer complementary reactivity to small-molecule catalysts. Hemoproteins, particularly cytochromes P450, have proven effective for selective oxidation of unactivated C-H bonds. Previously, we reported the in vitro characterization of an oxidative tailoring cascade in which TamI, a multifunctional P450 functions co-dependently with the TamL flavoprotein to catalyze regio- and stereoselective hydroxylations and epoxidation to yield tirandamycin A and tirandamycin B. TamI follows a defined order including 1) C10 hydroxylation, 2) C11/C12 epoxidation, and 3) C18 hydroxylation. Here we present a structural, biochemical, and computational investigation of TamI to understand the molecular basis of its substrate binding, diverse reactivity, and specific reaction sequence. The crystal structure of TamI in complex with tirandamycin C together with molecular dynamics simulations and targeted mutagenesis suggest that hydrophobic interactions with the polyene chain of its natural substrate are critical for molecular recognition. QM/MM calculations and molecular dynamics simulations of TamI with variant substrates provided detailed information on the molecular basis of sequential reactivity, and pattern of regio- and stereo-selectivity in catalyzing the three-step oxidative cascade.<br>

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

Connecting Remote C–H Bond Functionalization and Decarboxylative Coupling Using Simple Amines

2019 ◽  
Author(s):  
Francisco de Azambuja ◽  
Ming-Hsiu Yang ◽  
Alexander Bruecker ◽  
Paul Cheong ◽  
Ryan Altman
Keyword(s):  
Organic Molecules ◽  
Mechanistic Studies ◽  
Bond Functionalization ◽  
Bond Forming ◽  
Decarboxylative Coupling

The manuscript describes a Pd-catalyzed reaction of benzylic electrophiles that gives para-substituted arene products. Mechanistic studies suggest a mechanism involving a dearomative C–C bond-forming step, followed by base-mediated rearomatization. This mechanism is uncommon and underappreciated in Pd-catalysis and further exploitation of this mechanism should enable access to other organic molecules.

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