C-H Functionalization to Form C-O, C-N, and C-C Bonds

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Vinyl Ether ◽  
Boronic Acid ◽  
Bond Formation ◽  
University Of Maryland ◽  
Tsinghua University ◽  
Statistical Mixture ◽  
Mild Conditions ◽  
Hydride Abstraction ◽  
La Jolla ◽  
The University

A classic example of C-H functionalization is the familiar NBS bromination of a benzylic site. Recent updates of this approach allow for direct alkoxylation (J. Am. Chem. Soc. 2008, 130, 7824) and net amination (Organic Lett. 2008, 10, 1863). For the amination of simple aliphatic H’s, Holger F. Bettinger of Ruhr-Universität Bochum developed (Angew. Chem. Int. Ed. 2008, 47, 4744) the boryl azide 2. The insertion with 1 proceeded to give a statistical mixture of the nitrene insertion products 3 and 4. The tethered C-H functionalization devised (J. Am. Chem. Soc. 2008, 130, 7247) by Phil S. Baran of Scripps-La Jolla is selective, as in the conversion to 5 to 6, but appears to be limited to tertiary and benzylic C-H sites. Michael P. Doyle of the University of Maryland established (J. Org. Chem. 2008, 73, 4317) an elegant protocol for the oxidation of an alkyne such as 7 to the ynone 8. Note that the oxidation did not move the alkyne. Marta Catellani of the Università di Parma reported (Adv. Synth. Cat. 2008, 350, 565) the intriguing Pd-catalyzed conversion of 9 to 10. Under mild conditions, it might likely be possible to hydrolyze the vinyl ether to reveal the phenol 11. Another way of looking at this overall transformation would be to consider the ether 10 to be a protected form of the aldehyde 12. C-H activation can also lead to C-C bond formation. Irena S. Akhrem of the Nesmeyanov Institute, Moscow, described (Tetrahedron Lett. 2008, 49, 1399) a hydride-abstraction protocol for three-component coupling of a hydrocarbon 13 , an amine 14 , and CO, leading to the homologated amide 15. Hua Fu of Tsinghua University, Beijing, showed (J. Org. Chem. 2008 , 73, 3961) that oxidation of an amine 16 led to an intermediate that could be coupled with an alkyne 17 to give the propargylic amine 18. Products 15 and 18 are the result of sp2 and sp coupling, respectively. C-H functionalization leading to sp3 -sp3 coupling is less common. Jin-Quan Yu of Scripps/La Jolla found (J. Am. Chem. Soc. 2008, 130, 7190) that activation of the N-methoxy amide 19 in the presence of the alkyl boronic acid 20 gave smooth coupling, to 21.

C–H Functionalization: The Hatakeyama Synthesis of (–)-Kaitocephalin

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
University Of California ◽  
University Of Delaware ◽  
State University ◽  
Max Planck ◽  
Pennsylvania State University ◽  
University Of Illinois ◽  
University Of Houston ◽  
Hydride Abstraction ◽  
La Jolla ◽  
The University

John F. Hartwig of the University of California, Berkeley showed (Nature 2012, 483, 70) that intramolecular C–H silylation of 1 selectively gave, after oxidation and acetylation, the bis acetate 2. Gong Chen of Pennsylvania State University coupled (J. Am. Chem. Soc. 2012, 134, 7313) 3 with 4 to give the ether 5. M. Christina White of the University of Illinois effected (J. Am. Chem. Soc. 2012, 134, 9721) selective oxidation of the taxane derivative 6 to the lactone 7. Most of the work on C–H functionalization has focused on the formation of C–C, C–O, and C–N bonds. Donald A. Watson of the University of Delaware developed (Angew. Chem. Int. Ed. 2012, 51, 3663) conditions for the complementary conversion of an alkene 8 to the allyl silane 9, a powerful and versatile nucleophile. Kilian Muniz of ICIQ Tarragona oxidized (J. Am. Chem. Soc. 2012, 134, 7242) the enyne 10 selectively to the amine 11. Phil S. Baran of Scripps/La Jolla devised (J. Am. Chem. Soc. 2012, 134, 2547) a protocol for the OH-directed amination of 12 to 13. Professor White developed (J. Am. Chem. Soc. 2012, 134, 2036) a related OH-directed amination of 14 to 15 that proceeded with retention of absolute configuration. Tom G. Driver of the University of Illinois, Chicago showed (J. Am. Chem. Soc. 2012, 134, 7262) that the aryl azide 16 could be cyclized directly to the amine, which was protected to give 17. As illustrated by the conversion of 18 to 20 devised (Adv. Synth. Catal. 2012, 354, 701) by Martin Klussmann of the Max-Planck-Institut, Mülheim, C–H functionalization can be accomplished by hydride abstraction followed by coupling of the resulting carbocation with a nucleophile. Olafs Daugulis of the University of Houston used (Angew. Chem. Int. Ed. 2012, 51, 5188) a Pd catalyst to couple 21 with 22 to give 23 with high diastereocontrol. Yoshiji Takemoto of Kyoto University cyclized (Angew. Chem. Int. Ed. 2012, 51, 2763) the chloroformate 24 directly to the oxindole 25.

Substituted Benzenes: The Alvarez- Manzaneda Synthesis of (–)-Akaol A

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Bond Formation ◽  
University Of Michigan ◽  
Aromatic Substitution ◽  
Substituted Benzenes ◽  
University Of Oklahoma ◽  
Meta Position ◽  
Substitution Chemistry ◽  
La Jolla ◽  
The University ◽  
École Polytechnique

Ramin Ghorbani-Vaghei of Bu-Ali Sina University devised (Tetrahedron Lett. 2012, 53, 2325) conditions for the bromination of an electron-deficient arene such as 1. Yonghong Gu of the University of Science and Technology of China found (Tetrahedron Lett. 2011, 52, 4324) that an electron-rich anilide 3 could be oxidized to 4. Sukbok Chang of KAIST (J. Am. Chem. Soc. 2012, 134, 2528) and Kouichi Ohe of Kyoto University (Chem. Commun. 2012, 48, 3127) devised protocols for the oxidative cyanation of 5 to 6. Phenylazocarboxylates and triazenes are stable, but have the reaction chemistry of diazonium salts. The aromatic substitution chemistry of these derivatives has not been much explored. As illustrated by the conversion of 7 to 8, reported (J. Org. Chem. 2012, 77, 1520) by Markus R. Heinrich of the Universität Erlangen-Nürnberg, the benzene ring of the phenylazocarboxylate is reactive with nucleophiles. In contrast, triazene-activated benzene rings should be particularly reactive with electrophiles, as exemplified by the transformation, below, of 20 to 21. Melanie S. Sanford of the University of Michigan observed (Org. Lett. 2012, 14, 1760) good selectivity for 12 in the Pd-catalyzed reaction of 10 with 11. Jérôme Waser of the Ecole Polytechnique Fédérale de Lausanne used (Org. Lett. 2012, 14, 744) 14 to alkynylate 13 to give 15. Sulfonyl chlorides such as 16 are readily prepared from the corresponding arene, and many are commercially available. Jiang Cheng of Wenzhou University found (Chem. Commun. 2012, 48, 449) conditions for the direct cyanation of 16 to 17. Kenneth M. Nicholas of the University of Oklahoma effected (J. Org. Chem. 2012, 77, 5600) selective ortho bromination of the carbamate 18 to give 19. Stefan Bräse of KIT observed (Angew. Chem. Int. Ed. 2012, 51, 3713) ortho trifluoromethylation of the triazene 20 to give 21. Ji-Quan Yu of Scripps/La Jolla designed (Nature 2012, 486, 518) the benzyl ether 22 to activate the arene for C–C bond formation at the meta position to give 23. Guo-Jun Deng of Xiangtan University employed (Org. Lett. 2012, 14, 1692) a borrowed hydrogen strategy to effect aromatization of 24 with nitrobenzene to give the aniline 25.

scholarly journals Continuous-Flow Processes for the Production of Floxacin Intermediates: Efficient C–C Bond Formation through a Rapid and Strong Activation of Carboxylic Acids

2020 ◽  
Vol 02 (03) ◽  
pp. e128-e132
Author(s):  
Shao-Zheng Guo ◽  
Zhi-Qun Yu ◽  
Wei-Ke Su
Keyword(s):  
Reaction Time ◽  
Continuous Flow ◽  
Flow System ◽  
Bond Formation ◽  
Product Yield ◽  
Raw Material ◽  
Material Consumption ◽  
Tank Reactor ◽  
Mild Conditions ◽  
Flow Processes

AbstractThe development of highly efficient C–C bond formation methods for the synthesis of ethyl 2-(2,4-dichloro-5-fluorobenzoyl)-3-(dimethylamino)acrylate 1 in continuous flow processes has been described, which is based on the concept of rapid and efficient activation of carboxylic acid. 2,4-Dichloro-5-fluorobenzoic acid is rapidly converted into highly reactive 2,4-dichloro-5-fluorobenzoyl chloride by treating with inexpensive and less-toxic solid bis(trichloromethyl)carbonate. And then it rapidly reacts with ethyl 3-(dimethylamino)acrylate to afford the desired 1. This process can be performed under mild conditions. Compared with the traditional tank reactor process, less raw material consumption, higher product yield, less reaction time, higher operation safety ensured by more the environmentally friendly procedure, and process continuity are achieved in the continuous-flow system.

scholarly journals The McDonaldization of Academic Libraries?

2015 ◽  
Vol 76 (3) ◽  
pp. 339-352 ◽  
Author(s):  
Brian Quinn
Keyword(s):  
Academic Libraries ◽  
Fast Food ◽  
Food Industry ◽  
Fast Food Industry ◽  
University Of Maryland ◽  
The University

George Ritzer, a sociologist at the University of Maryland, has proposed an influential thesis that suggests that many aspects of the fast food industry are making their way into other areas of society. This article explores whether his thesis, known as the McDonaldization thesis, is applicable to academic libraries. Specifically, it seeks to determine to what extent academic libraries may be considered McDonaldized, and if so, what effect McDonaldization may be having on them. It also investigates some possible alternatives to McDonaldization, and their implications for academic libraries.

Development of Team Coordination and Performance Measures in a Trauma Setting

2007 ◽  
Vol 51 (11) ◽  
pp. 717-721 ◽  
Author(s):  
Stuart Marshall ◽  
Anne Miller ◽  
Yan Xiao
Keyword(s):  
Team Performance ◽  
Decision Support Tool ◽  
Stage Model ◽  
Trauma Resuscitation ◽  
Team Coordination ◽  
Support Tool ◽  
University Of Maryland ◽  
Performance Metric ◽  
And Performance ◽  
The University

The paucity of reliable measures of team coordination and performance significantly obstructs the assessment of the effects of any technology on teams to improve decision making in health care. A pilot study was conducted to determine if measures of coordination and performance could be developed for teams involved in trauma resuscitation. A video assisted review of cases enabled evaluation of the use of the tools. Descriptors of coordination were derived from Klein's five-stage model of team coordination. A scoring system of team performance was developed from the University of Maryland Team Observable Performance Metric (UMTOP). After some modification both coordination and performance could be described. However, four defined stages of resuscitation were observed which greatly improved coding. More rigorous assessments of these tools will be required before firm conclusions can be drawn about the effects of a decision support tool recently introduced into the environment.

The University of Maryland, Maryland Advanced Simulation, Training, Research and Innovation (MASTRI) Center

2010 ◽  
Vol 67 (6) ◽  
pp. 473-476 ◽  
Author(s):  
Gerald Moses ◽  
F. Jacob Seagull ◽  
Erica Sutton ◽  
Gyusung Lee ◽  
Ivan George ◽  
...  
Keyword(s):  
Simulation Training ◽  
University Of Maryland ◽  
Research And Innovation ◽  
Training Research ◽  
The University
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