Organic Functional Group Protection and Deprotection

Author(s):  
Douglass F. Taber

Martin Oestreich of the Technische Universität Berlin developed (Eur. J. Org. Chem. 2014, 2077) the Birch reduction product 2 as a donor for the silylation of an alco­hol 1 to give 3. Atahualpa Pinto of the SUNY College of Environmental Science and Forestry devised (Tetrahedron Lett. 2014, 55, 2600) conditions for the monosilylation of the diol 4 to give 5. Quanxuan Zhang of Michigan State University reported (Tetrahedron Lett. 2014, 55, 3384) the preparation (not illustrated) of the mono-THP ethers of symmetrical diols. The product from the Mitsunobu cou­pling of an acid with an alcohol 6 can be difficult to purify. Takashi Sugimura of the University of Hyogo showed (Synthesis 2013, 45, 931) that the oxidation product from 7 and the reduction product from 8 could both be removed from the product 9 by simple extraction. David Milstein of the Weizmann Institute of Science found (Angew. Chem. Int. Ed. 2014, 53, 4685) that an Fe catalyst could be used to reduce the trifluoroacetate 10 to 11. Jean-Michel Vatèle of the Université Lyon 1 oxidized (Synlett 2014, 25, 115) the benzylidene acetal 12 selectively to the monobenzoate 13. Xinyu Liu of the University of Pittsburgh organized (Chem. Commun. 2014, 50, 3155) a family of acid-sensitive esters that can be selectively removed in the presence of other esters, as exemplified by the conversion of 14 to 15. Ryo Yazaki and Takashi Ohshima of Kyushu University observed (Angew. Chem. Int. Ed. 2014, 53, 1611) that an amine would add spontaneously to acrylonitrile 17 to give 18. In the presence of a Cu catalyst, alcohols added to 17 even more readily, allowing the preparation of 18 from 16. Diego Gamba-Sánchez of the Universidad de los Andes used (J. Org. Chem. 2014, 79, 4544) simple Fe catalysts to activate a wide range of amides, including 20, to become acylating agents, converting 19 to 21. 1,2-Addition to t-butylsulfanylimines is widely used to construct aminated stereo­genic centers. Xiaodong Yang and Hongbin Zhang of Yunnan University established (Chem. Commun. 2014, 50, 6259) a general protocol for cleaving the N–S bond in the product 22 to give the desired free amine 23.

Author(s):  
Douglass Taber

Both 1 and 3 are inexpensive prochiral starting materials. Tae-Jong Kim of Kyungpook National University devised (Organomet. 2008, 27, 1026) a chiral Cu catalyst that efficiently converted 1 (other ring sizes worked as well) to the enantiomerically pure ester 2. Alexandre Alexakis of the University of Geneva found (Adv. Synth. Cat. 2008, 350, 1090) a chiral Cu catalyst that mediated the enantioselective coupling of 3 with Grignard reagents such as 4 . The π-allyl Pd complex derived from 6 is also prochiral. Barry M. Trost of Stanford University showed (Angew. Chem. Int. Ed. 2008, 47, 3759) that with appropriate ligand substitution, coupling with the phthalimide 7 proceeded to give 8, readily convertible to (-)-oseltamivir (Tamiflu) 9, in high ee. Jonathan W. Burton of the University of Oxford found (Chem Commun. 2008, 2559) that Mn(OAc)3 -mediated cyclization of 10 delivered the lactone 12 with high diastereocontrol. John Montgomery of the University of Michigan observed (Organic Lett. 2008, 10, 811) that the Ni-catalyzed cyclization of 12 also proceeded with high diastereocontrol. Ken Tanaka of the Tokyo University of Agriculture and Technology combined (Angew. Chem. Int. Ed. 2008, 47, 1312) Rh-catalyzed ene-yne cyclization of 14 with catalytic ortho C-H functionalization, leading to 16 in high ee. Eric N. Jacobsen of Harvard University designed (Angew. Chem. Int. Ed. 2008, 47, 1469) a chiral Cr catalyst for the intramolecular carbonyl ene reaction, that converted 17 to 18 in high ee. Using a stoichiometric prochiral Cr carbene complex 20 and the enantiomerically-pure secondary propargylic ether 19, Willam D. Wulff of Michigan State University prepared (J. Am. Chem. Soc. 2008, 130, 2898) a facially-selective Cr-complexed o -quinone methide intermediate, that cyclized to 21 with high ee. A variety of methods have been put forward for the transition metal-mediated construction of polycarbocyclic systems. One of the more powerful is the enantioselective Rh-catalyzed stitching of the simple substrate 22 into the tricycle 23 devised (J. Am. Chem. Soc. 2008, 130, 3451) by Takanori Shibata of Waseda University. Inter alia, ozonolysis of 23 delivered the cyclopentane 24 containing two all-carbon quaternary centers.


Neurosurgery ◽  
2008 ◽  
Vol 63 (5) ◽  
pp. 874-879 ◽  
Author(s):  
Archit Bhatt ◽  
Nirav A. Vora ◽  
Ajith J. Thomas ◽  
Arshad Majid ◽  
Mounzer Kassab ◽  
...  

Abstract OBJECTIVE Intra-arterial therapies are being used more frequently in patients presenting with acute cerebral occlusions, but they have been limited by the potential for hemorrhage. We sought to determine whether pretreatment computed tomography perfusion parameters might help to identify patients at a higher risk of developing intracranial hemorrhage after intra-arterial stroke revascularization treatment. METHODS We retrospectively reviewed all patients at the University of Pittsburgh Medical Center and Michigan State University who underwent computed tomography perfusion imaging of the brain before intra-arterial thrombolysis between January 2006 and June 2007. Demographic information, angiographic variables, and types of endovascular interventions were recorded. The mean transit time and cerebral blood volumes were recorded for the ipsilateral and contralateral middle cerebral artery territories. A binary logistic regression model was constructed to determine the independent predictors of developing intracranial hemorrhage. RESULTS A total of 57 patients (33 from the University of Pittsburgh and 24 from Michigan State University) with a mean age of 66 ± 13 years and mean National Institutes of Health Stroke Scale scores of 16 ± 5 were studied. The overall recanalization (Thrombolysis in Myocardial Infarction Trial scale 2 or 3 flow) was 72% for the cohort, and the overall rate of parenchymal hemorrhage was 5 of 57 (9%) patients. The overall hemorrhage rate was 19 of 57 (33%) patients. The only variable found to be predictive of the development of hemorrhage after intervention was reduced pretreatment cerebral blood volume (odds ratio, 0.49; 95% confidence interval, 0.35–0.91; P < 0.022). CONCLUSION A reduced pretreatment ipsilateral cerebral blood volume value before endovascular revascularization of an acute middle cerebral artery or internal carotid artery occlusion significantly increases the risk of an intracranial hemorrhage.


1973 ◽  
Vol 2 (2) ◽  
pp. 297-304
Author(s):  
Daymon W. Thatch ◽  
William L. Park

Rutgers University was chartered as Queen's College on November 10, 1766. It was the eighth institution of higher education founded in Colonial America prior to the Revolutionary War. From its modest beginning in the New Brunswick area the University has grown to eight separately organized undergraduate colleges in three areas of the State, with a wide range of offerings in liberal and applied arts and sciences.


2016 ◽  
Vol 6 (4) ◽  
pp. 209-223

During the university course the future legal psychologists have to master a wide range of professional competencies, among them are those that can be classified as management, with an emphasis on project making competencies and their relationship with the project making professional culture. The article presents the results of students' self-evaluation competencies. This research was a part of the monitoring of learning outcomes in a number of disciplines in the Faculty of Legal Psychology, Moscow State University of Psychology and Education. The author raises the problem of defining the concepts of "project culture" and "psychological culture of project making", which still do not have a clear definition inspite of the intensive development of the socio-cultural, innovative and other forms of project making. For legal psychologists project making culture involves the acquisition of psychologically correct approaches to the development, evaluation, promotion and institutionalization of the ideas, so they can provide the solution of professional problems.


Author(s):  
Douglass Taber

Chaozhong Li of the Shanghai Institute of Organic Chemistry demonstrated (Organic Lett. 2008, 10, 4037) facile and selective Cu-catalyzed β-lactam formation, converting 1 to 2. Paul Helquist of the University of Notre Dame devised (Organic Lett. 2008, 10, 3903) an effective catalyst for intramolecular alkyne hydroamination, converting 3 into the imine 4. Six-membered ring construction worked well also. Jon T. Njardarson of Cornell University found (Organic Lett. 2008, 10, 5023) a Cu catalyst for the rearrangement of alkenyl aziridines such as 5 to the pyrroline 6. Philippe Karoyan of the UPMC, Paris developed (J. Org. Chem. 2008, 73, 6706) an interesting chiral auxiliary directed cascade process, converting the simple precursor 7 into the complex pyrrolidine 9. Sherry R. Chemler of the State University of New York, Buffalo devised (J. Am. Chem. Soc. 2008, 130, 17638) a chiral Cu catalyst for the cyclization of 10, to give 12 with substantial enantiocontrol. Wei Wang of the University of New Mexico demonstrated (Chem. Commun. 2008, 5636) the organocatalyzed condensation of 13 and 14 to give 16 with high enantio- and diastereocontrol. Two complementary routes to azepines/azepinones have appeared. F. Dean Toste of the University of California, Berkeley showed (J. Am. Chem. Soc. 2008, 130, 9244) that a gold complex catalyzed the condensation of 17 and 18 to give 19. Frederick G. West of the University of Alberta found (Organic Lett. 2008, 10, 3985) that lactams such as 20 could be ring-expanded by the addition of the propiolate anion 21. Takeo Kawabata of Kyoto University extended (Organic Lett . 2008, 10, 3883) “memory of chirality” studies to the cyclization of 23, demonstrating that 24 was formed in high ee. Paul V. Murphy of University College Dublin took advantage (Organic Lett . 2008, 10, 3777) of the well-known intramolecular addition of azides to alkenes, showing that the intermediate could be intercepted with nucleophiles such as thiophenol, to give the cyclized product 26 with high diastereocontrol.


Author(s):  
Douglass Taber

Since five-membered ring ethers often do not show good selectivity on equilibration, single diastereomers are best formed under kinetic control. Aaron Aponick of the University of Florida demonstrated (Organic Lett. 2008, 10, 669) that under gold catalysis, the allylic alcohol 1 cyclized to 2 with remarkable diastereocontrol. Six-membered rings also formed with high cis stereocontrol. Ian Cumpstey of Stockholm University showed (Chem. Commun. 2008, 1246) that with protic acid, allylic acetates such as 3 cyclized with clean inversion at the allylic center, and concomitant debenzylation. J. Stephen Clark of the University of Glasgow found (J. Org. Chem. 2008, 73, 1040) that Rh catalyzed cyclization of 5 proceeded with high selectivity for insertion into Ha, leading to the alcohol 6. Saumen Hajra of the Indian Institute of Technology, Kharagpur took advantage (J. Org. Chem. 2008, 73, 3935) of the reactivity of the aldehyde of 7, effecting selective addition of 7 to 8, to deliver, after reduction, the lactone 9. Tomislav Rovis of Colorado State University observed (J. Org. Chem. 2008, 73, 612) that 10 could be cyclized selectively to either 11 or 12. Nadège Lubin-Germain, Jacques Uziel and Jacques Augé of the University of Cergy- Pontoise devised (Organic Lett. 2008, 10, 725) conditions for the indium-mediated coupling of glycosyl fluorides such as 13 with iodoalkynes such as 14 to give the axial C-glycoside 15. Katsukiyo Miura and Akira Hosomi of the University of Tsukuba employed (Chemistry Lett. 2008, 37, 270) Pt catalysis to effect in situ equilibration of the alkene 16 to the more stable regioisomer. Subsequent condensation with the aldehyde 17 led via Prins cyclization to the ether 18. Paul E. Floreancig of the University of Pittsburgh showed (Angew. Chem. Int. Ed. 2008, 47, 4184) that Prins cyclization could be also be initiated by oxidation of the benzyl ether 19 to the corresponding carbocation. Chan-Mo Yu of Sungkyunkwan University developed (Organic Lett. 2008, 10, 265) a stereocontrolled route to seven-membered ring ethers, by Pd-mediated stannylation of allenes such as 21, followed by condensation with an aldehyde.


Author(s):  
Douglass F. Taber

Jianbo Wang of Peking University described (Angew. Chem. Int. Ed. 2010, 49, 2028) the Au-promoted bromination of a benzene derivative such as 1 with N-bromosuccinimide. In a one-pot procedure, addition of a Cu catalyst followed by microwave heating delivered the aminated product 2. Jian-Ping Zou of Suzhou University and Wei Zhang of the University of Massachusetts, Boston, observed (Tetrahedron Lett. 2010, 51, 2639) that the phosphonylation of an arene 3 proceeded with substantial ortho selectivity. Yonghong Gu of the University of Science and Technology, Hefei, showed (Tetrahedron Lett. 2010, 51, 192) that an arylpropanoic acid 6 could be ortho hydroxylated with PIFA to give 7. Louis Fensterbank, Max Malacria, and Emmanuel Lacôte of UMPC Paris found (Angew. Chem. Int. Ed. 2010, 49, 2178) that a benzoic acid could be ortho aminated by way of the cyano amide 8. Daniel J. Weix of the University of Rochester developed (J. Am. Chem. Soc. 2010, 132, 920) a protocol for coupling an aryl iodide 10 with an alkyl iodide 11 to give 12. Professor Wang devised (Angew. Chem. Int. Ed. 2010, 49, 1139) a mechanistically intriguing alkyl carbonylation of an iodobenzene 10. This is presumably proceeding by way of the intermediate diazo alkane. Usually, benzonitriles are prepared by cyanation of the halo aromatic. Hideo Togo of Chiba University established (Synlett 2010, 1067) a protocol for the direct electrophilic cyanation of an electron-rich aromatic 15. Thomas E. Cole of San Diego State University observed (Tetrahedron Lett. 2010, 51, 3033) that an alkyl dimethyl borane, readily prepared by hydroboration of the alkene with BCl3 and Et3 SiH, reacted with benzoquinone 17 to give 18. Presumably this transformation could also be applied to substituted benzoquinones. When a highly substituted benzene derivative is needed, it is sometimes more economical to construct the aromatic ring. Joseph P. A. Harrity of the University of Sheffield and Gerhard Hilt of Philipps-Universität Marburg showed (J. Org. Chem. 2010, 75, 3893) that the Co-catalyzed Diels-Alder cyloaddition of alkynyl borinate 21 with a diene 20 proceeded with high regiocontrol, to give, after oxidation, the aryl borinate 22.


2017 ◽  
Vol 6 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Daniel Gould

The mission of the Institute for the Study of Youth Sports (ISYS) is to provide leadership, scholarship, and outreach that “transforms” the face of youth sports in ways that maximize the beneficial physical, psychological, and social effects of participation for children and youth while minimizing detrimental effects. Since its inception in 1978, ISYS has partnered with numerous organizations to promote healthy youth sports participation. In this article, the general steps ISYS takes to form and facilitate partnerships are addressed. Four long-term partnerships are also described. The services provided to these organizations are described and the advantages and challenges of working with partners, in general, are delineated. How these partnerships are used to facilitate the teaching, outreach-engagement, and scholarship components of the Michigan State University land grant mission are also described. The case of ISYS shows that conducting community outreach and engagement projects greatly enhance the scholarly mission of the university.


2015 ◽  
Vol 53 (1) ◽  
pp. 118-119

Theodore Burczak of Denison University reviews “Documents Related to John Maynard Keynes, Institutionalism at Chicago and Frank H. Knight”, by Ross B. Emmett. The Econlit abstract of this book begins: “Eight papers explore topics related to John Maynard Keynes, institutionalism at the University of Chicago, and Frank H. Knight. Papers discuss the original 1933 “National Self-Sufficiency” lecture by Keynes—its political economic context and purpose (Mark C. Nolan); “National Self-Sufficiency” (Keynes); studying institutional economics at Chicago in the 1930s—the case of Arthur Bloomfield (Pier Francesco Asso and Luca Fiorito); Thorstein Veblen and his analysis of business enterprise (Bloomfield); Knight on institutionalism and economics (Ross B. Emmett); institutional history and the classical economics (Knight); the friendship of Knight and Frederick D. Kershner (Emmett); and the correspondence between Knight and Kershner, 1915-51 (Emmett). Emmett is at James Madison College at Michigan State University.”


Sign in / Sign up

Export Citation Format

Share Document