Functional Group Protection: The Pohl Synthesis of β-1,4-Mannuronate Oligomers

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Gold Catalyst ◽  
State University ◽  
Allyl Ester ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Benzyl Ethers ◽  
Institute Of Technology ◽  
Tokyo Medical ◽  
The University

D. Srinivasa Reddy of the National Chemical Laboratory converted (Org. Lett. 2015, 17, 2090) the selenide 1 to the alkene 2 under ozonolysis conditions. Takamitsu Hosoya of the Tokyo Medical and Dental University found (Chem. Commun. 2015, 51, 8745) that even highly strained alkynes such as 4 can be generated from a sulfinyl vinyl triflate 3. An alkyne can be protected as the dicobalt hexacarbonyl complex. Joe B. Gilroy and Mark S. Workentin of the University of Western Ontario found (Chem. Commun. 2015, 51, 6647) that following click chemistry on a non-protected distal alkyne, deprotection of 5 to 6 could be effected by exposure to TMNO. Stefan Bräse of the Karlsruhe Institute of Technology and Irina A. Balova of Saint Petersburg State University showed (J. Org. Chem. 2015, 80, 5546) that the bend of the Co complex of 7 enabled ring-closing metathesis, leading after deprotection to 8. Morten Meldal of the University of Copenhagen devised (Eur. J. Org. Chem. 2015, 1433) 9, the base-labile protected form of the aldehyde 10. Nicholas Gathergood of Dublin City University and Stephen J. Connon of the University of Dublin developed (Eur. J. Org. Chem. 2015, 188) an imidazolium catalyst for the exchange deprotection of 11 to 13, with the inexpensive aldehyde 12 as the acceptor. Peter J. Lindsay-Scott of Eli Lilly demonstrated (Org. Lett. 2015, 17, 476) that on exposure to KF, the isoxa­zole 14 unraveled to the nitrile 15. Masato Kitamura of Nagoya University observed (Tetrahedron 2015, 71, 6559) that the allyl ester of 16 could be removed to give 17, with the other alkene not affected. Benzyl ethers are among the most common of alcohol protecting groups. Yongxiang Liu and Maosheng Cheng of Shenyang Pharmaceutical University showed (Adv. Synth. Catal. 2015, 357, 1029) that 18 could be converted to 19 simply by expo­sure to benzyl alcohol in the presence of a gold catalyst. Reko Leino of Åbo Akademi University developed (Synthesis 2015, 47, 1749) an iron catalyst for the reductive benzylation of 20 to 21. Related results (not illustrated) were reported (Org. Lett. 2015, 17, 1778) by Chae S. Yi of Marquette University.

Organocatalyzed C–C Ring Construction: The Mihovilovic Synthesis of Piperenol B

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
State University ◽  
Air Oxidation ◽  
Microbial Oxidation ◽  
Max Planck ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Northwestern University ◽  
National University ◽  
The University ◽  
Oregon State University

M. Kevin Brown of Indiana University prepared (J. Am. Chem. Soc. 2015, 137, 3482) the cyclobutane 3 by the organocatalyzed addition of 2 to the alkene 1. Karl Anker Jørgensen of Aarhus University assembled (J. Am. Chem. Soc. 2015, 137, 1685) the complex cyclobutane 7 by the addition of 5 to the acceptor 4, followed by conden­sation with the phosphorane 6. Zhi Li of the National University of Singapore balanced (ACS Catal. 2015, 5, 51) three enzymes to effect enantioselective opening of the epoxide 8 followed by air oxidation to 9. Gang Zhao of the Shanghai Institute of Organic Chemistry and Zhong Li of the East China University of Science and Technology added (Org. Lett. 2015, 17, 688) 10 to 11 to give 12 in high ee. Akkattu T. Biju of the National Chemical Laboratory combined (Chem. Commun. 2015, 51, 9559) 13 with 14 to give the β-lactone 15. Paul Ha-Yeon Cheong of Oregon State University and Karl A. Scheidt of Northwestern University reported (Chem. Commun. 2015, 51, 2690) related results. Dieter Enders of RWTH Aachen University constructed (Chem. Eur. J. 2015, 21, 1004) the complex cyclopentane 20 by the controlled com­bination of 16, 17, and 18, followed by addition of the phosphorane 19. Derek R. Boyd and Paul J. Stevenson of Queen’s University Belfast showed (J. Org. Chem. 2015, 80, 3429) that the product from the microbial oxidation of 21 could be protected as the acetonide 22. Ignacio Carrera of the Universidad de la República described (Org. Lett. 2015, 17, 684) the related oxidation of benzyl azide (not illustrated). Manfred T. Reetz of the Max-Planck-Institut für Kohlenforschung and the Philipps-Universität Marburg found (Angew. Chem. Int. Ed. 2014, 53, 8659) that cytochrome P450 could oxidize the cyclohexane 23 to the cyclohexanol 24. F. Dean Toste of the University of California, Berkeley aminated (J. Am. Chem. Soc. 2015, 137, 3205) the ketone 25 with 26 to give 27. Benjamin List, also of the Max-Planck-Institut für Kohlenforschung, reported (Synlett 2015, 26, 1413) a parallel investigation. Philip Kraft of Givaudan Schweiz AG and Professor List added (Angew. Chem. Int. Ed. 2015, 54, 1960) 28 to 29 to give 30 in high ee.

Organocatalyzed C–C Ring Construction: The Bradshaw/Bonjoch Synthesis of (−)-Cermizine B

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
San Antonio ◽  
Bond Formation ◽  
Bryn Mawr ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Enantiomerically Pure ◽  
University Of Texas ◽  
National University ◽  
Institute Of Technology ◽  
The University

In a continuation of his studies (OHL20141229, OHL20140811) of organocatalyzed 2+2 photocycloaddition, Thorsten Bach of the Technische Universität München assembled (Angew. Chem. Int. Ed. 2014, 53, 7661) 3 by adding 2 to 1. Li-Xin Wang of the Chengdu Institute of Organic Chemistry also used (Org. Lett. 2014, 16, 6436) an organocatalyst to effect the addition of 5 to 4 to give 6. Shuichi Nakamura of the Nagoya Institute of Technology devised (Org. Lett. 2014, 16, 4452) an organocatalyst that mediated the enantioselective opening of the aziridine 7 to 8. Zhi Li of the National University of Singapore cloned (Chem. Commun. 2014, 50, 9729) an enzyme from Acinetobacter sp. RS1 that reduced 9 to 10. Gregory C. Fu of Caltech developed (Angew. Chem. Int. Ed. 2014, 53, 13183) a phosphine catalyst that directed the addition of 12 to 11 to give 13. Armido Studer of the Westfälische Wilhelms-Universität Münster showed (Angew. Chem. Int. Ed. 2014, 53, 9622) that 15 could be added to 14 to give 16 in high ee. Akkattu T. Biju of CSIR-National Chemical Laboratory described (Chem. Commun. 2014, 50, 14539) related results. The photostimulated enantioselective ketone alkylation developed (Chem. Sci. 2014, 5, 2438) by Paolo Melchiorre of ICIQ was powerful enough to enable the alkyl­ation of 17 with 18 to give 19, overcoming the stereoelectronic preference for axial bond formation. David W. Lupton of Monash University established (J. Am. Chem. Soc. 2014, 136, 14397) the organocatalyzed transformation of the dienyl ester 20 to 21. James McNulty of McMaster University added (Angew. Chem. Int. Ed. 2014, 53, 8450) azido acetone 23 to 22 to give 24 in high ee. There are sixteen enantiomerically-pure diastereomers of the product 27. John C.-G. Zhao of the University of Texas at San Antonio showed (Angew. Chem. Int. Ed. 2014, 53, 7619) that with the proper choice of organocatalyst, with or without subsequent epimerization, it was possible to selectively prepare any one of eight of those diastereomers by the addition of 26 to 25. William P. Malachowski of Bryn Mawr College showed (Tetrahedron Lett. 2014, 55, 4616) that 28, readily prepared by a Birch reduction protocol, was converted by heating followed by exposure to catalytic Me3P to the angularly-substituted octalone 29.

C–N Ring Construction: The Hattori Synthesis of (+)-Spectaline

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Gold Catalyst ◽  
Ring Expansion ◽  
Homoserine Lactone ◽  
Amide Bond ◽  
State University ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Colorado State University ◽  
Schwartz Reagent ◽  
Rh Catalyst

Magnus Rueping of RWTH Aachen University found (Chem. Commun. 2015, 51, 2111) that under Fe catalysis, a Grignard reagent would couple with the iodoazetidine 1 to give the substituted azetidine 2. Timothy F. Jamison of MIT established (Chem. Eur. J. 2015, 21, 7379) a protocol for converting 3, readily available from commercial homoserine lactone, to the alkylated azetidine 4. Long-Wu Ye of Xiamen University used (Chem. Commun. 2015, 51, 2126) a gold catalyst to cyclize 5, readily prepared in high ee, to the versatile ene sulfonamide 6. Chang- Hua Ding and Xue-Long Hou of the Shanghai Institute of Organic Chemistry added (Angew. Chem. Int. Ed. 2015, 54, 1604) the racemic aziridine 7 to the enone 8 to give the pyrrolidine 9 in high ee. Arumugam Sudalai of the National Chemical Laboratory employed (J. Org. Chem. 2015, 80, 2024) proline as an organocatalyst to mediate the addition of 11 to 10, leading to the pyrrolidine 12. Aaron D. Sadow of Iowa State University developed (J. Am. Chem. Soc. 2015, 137, 425) a Zr catalyst for the enantioselective cyclization of the prochiral 13 to 14. Masahiro Murakami of Kyoto University devised (Angew. Chem. Int. Ed. 2015, 54, 7418) a Rh catalyst for the enantioselective ring expansion of the photocycliza­tion product of 15 to the enamine 16. Sebastian Stecko and Bartlomiej Furman of the Polish Academy of Sciences reduced (J. Org. Chem. 2015, 80, 3621) the carbohydrate-derived lactam 17 with the Schwartz reagent to give an intermediate that could be coupled with an isonitrile, leading to the amide 18. Lei Liu of Shandong University oxidized (Angew. Chem. Int. Ed. 2015, 54, 6012) the alkene 19 in the presence of 20 to give 21. Tomislav Rovis of Colorado State University optimized (J. Am. Chem. Soc. 2015, 137, 4445) a Zn catalyst for the addition of 22 to the nitro alkene 23, leading, after reduction, to the piperidine 24. Carlos del Pozo and Santos Fustero of the Universidad de Valencia used (Org. Lett. 2015, 17, 960) a chiral auxiliary to direct the cyclization of 25 to the bicyclic amine 26. In another illustration of the use of microwave irradiation to activate amide bond rotation, G. Maayan of Technion showed (Org. Lett. 2015, 17, 2110) that 27 could be cyclized efficiently to the medium ring lactam 28.

Reactions of Alkenes: The Usami Synthesis of (−)-Pericosine E

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Aldol Condensation ◽  
Indian Institute ◽  
Ortho Position ◽  
State University ◽  
Air Oxidation ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Georgia State University ◽  
Institute Of Technology ◽  
La Jolla

Dasheng Leow of the National Tsing Hua University used (Eur. J. Org. Chem. 2014, 7347) photolysis to activate the air oxidation of hydrazine to generate diimide, that then reduced 1 selectively to 2. Kevin M. Peese of Bristol-Myers Squibb effected (Org. Lett. 2014, 16, 4444) ring-closing metathesis of 3 followed by in situ reduction to form 4. Jitendra K. Bera of the Indian Institute of Technology Kanpur effected (J. Am. Chem. Soc. 2014, 136, 13987) gentle oxidative cleavage of cyclooctene 5 to the dialde­hyde 6. Arumugam Sudalai of the National Chemical Laboratory observed (Org. Lett. 2014, 16, 5674) high regioselectivity in the oxidation of the alkene 7 to the ketone 8. Hao Xu of Georgia State University also observed (J. Am. Chem. Soc. 2014, 136, 13186) high regioselectivity in the oxidation of the alkene 9 with 10, leading to the urethane 11. Justin Du Bois of Stanford University developed (J. Am. Chem. Soc. 2014, 136, 13506) mild conditions for the net double amination of the alkene 12 with 13, leading to 14. Jiaxi Xu and Pingfan Li of the Beijing University of Chemical Technology devised (Org. Lett. 2014, 16, 6036) a protocol for the allylic thiomethylation of an alkene with 16, converting 15 to 17. Matthias Beller of the Leibniz-Institüt für Katalyse combined (Chem. Eur. J. 2014, 20, 15692) hydroformylation, aldol condensation, and reduction to convert the alkene 18 to the ketone 19. Phil S. Baran of Scripps/La Jolla added (Angew. Chem. Int. Ed. 2014, 53, 14382) the diazo dienone 21 to the alkene 20 to give, after exposure to HCl, the arylated product 22. Markus R. Heinrich of the Friedrich-Alexander-Universität Erlangen-Nürnberg employed (Chem. Eur. J. 2014, 20, 15344) Selectfluor as both an oxidizing and a fluorinating agent in the related addition of 24 to 23 to give 25. Debabrata Maiti at the Indian Institute of Technology Bombay activated (J. Am. Chem. Soc. 2014, 136, 13602) the ortho position of 27, then added that interme­diate to 26 to give 28.

Metal-Mediated C–C Ring Construction: The Ding Synthesis of (−)-Indoxamycin B

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Claisen Rearrangement ◽  
Iron Catalyst ◽  
Gold Catalyst ◽  
State University ◽  
Relative Configuration ◽  
University Of Texas ◽  
Diethyl Zinc ◽  
Single Diastereomer ◽  
The University ◽  
Oregon State University

Shou-Fei Zhu of Nankai University developed (Angew. Chem. Int. Ed. 2014, 53, 13188) an iron catalyst that effected the enantioselective cyclization of 1 to 2. Bypassing diazo precursors, Junliang Zhang of East China Normal University used (Angew. Chem. Int. Ed. 2014, 53, 13751) a gold catalyst to cyclize 3 to 4. Taking advantage of energy transfer from a catalytic Ir complex, Chuo Chen of University of Texas Southwestern carried out (Science 2014, 346, 219) intramolec­ular 2+2 cycloaddition of 5, leading, after dithiane formation, to the cyclobutane 6. Intramolecular ketene cycloaddition has been limited in scope. Liming Zhang of the University of California Santa Barbara found (Angew. Chem. Int. Ed. 2014, 53, 9572) that intramolecular oxidation of an intermediate Ru vinylidene led to a species that cyclized to the cyclobutanone 8. James D. White of Oregon State University devised (J. Am. Chem. Soc. 2014, 136, 13578) an iron catalyst that mediated the enantioselective Conia-ene cyclization of 9 to 10. Xiaoming Feng of Sichuan University observed (Angew. Chem. Int. Ed. 2014, 53, 11579) that the Ni-catalyzed Claisen rearrangement of 11 proceeded with high diastereo- and enantiocontrol. The relative configuration of the product 12 was not reported. Robert H. Grubbs of Caltech showed (J. Am. Chem. Soc. 2014, 136, 13029) that ring opening cross metathesis of 13 with 14 delivered the Z product 15. Mn(III) cyclization has in the past required a stoichiometric amount of inorganic oxidant. Sangho Koo of Myong Ji University found (Adv. Synth. Catal. 2014, 356, 3059) that by adding a Co co- catalyst, air could serve as the stoichiometric oxidant. Indeed, 16 could be cyclized to 17 using inexpensive Mn(II). Matthias Beller of the Leibniz-Institüt für Katalyse prepared (Angew. Chem. Int. Ed. 2014, 53, 13049) the cyclohexene 20 by coupling the racemic alcohol 18 with the amine 19. Paultheo von Zezschwitz of Philipps-Universität Marburg added (Chem. Commun. 2014, 50, 15897) diethyl zinc in a conjugate sense to 21, then reduced the product to give 22. Depending on the reduction method, either diastereomer of the product could be made dominant. Nuno Maulide of the University of Vienna dis­placed (Angew. Chem. Int. Ed. 2014, 53, 7068) the racemic chloride 23 with diethyl zinc to give 24 as a single diastereomer.

Substituted Benzenes: The Reddy Synthesis of Isofregenedadiol

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Rhode Island ◽  
Benzene Derivative ◽  
Allyl Ester ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
University Of Technology ◽  
Simple Protocol ◽  
Peking University ◽  
The University ◽  
Technological University

Jianbo Wang of Peking University (Org. Lett. 2011, 13, 4988) and Patrick Y. Toullec and Véronique Michelet of Chimie ParisTech (Org. Lett. 2011, 13, 6086) developed conditions for the electrophilic acetoxylation of a benzene derivative 1. Seung Hwan Cho and Sukbok Chang of KAIST (J. Am. Chem. Soc. 2011, 133, 16382) and Brenton DeBoef of the University of Rhode Island (J. Am. Chem. Soc. 2011, 133, 19960) devised protocols for the electrophilic imidation of a benzene derivative 3. Vladimir V. Grushin of ICIQ Tarragona devised (J. Am. Chem. Soc. 2011, 133, 10999) a simple protocol for the cyanation of a bromobenzene 6 to the nitrile 7. Hua-Jian Xu of the Hefei University of Technology (J. Org. Chem. 2011, 76, 8036) and Myung-Jong Jin of Inha University (Org. Lett. 2011, 13, 5540) established conditions for the efficient Heck coupling of a chlorobenzene 8. Jacqueline E. Milne of Amgen/Thousand Oaks reduced (J. Org. Chem. 2011, 76, 9519) the adduct from the addition of 11 to 12 to deliver the phenylacetic acid 13. Jeffrey W. Bode of ETH Zurich effected (Angew. Chem. Int. Ed. 2011, 50, 10913) Friedel-Crafts alkylation of 14 with the hydroxamate 15 to give the meta product 16. B.V. Subba Reddy of the Indian Institute of Chemical Technology, Hyderabad took advantage (Tetrahedron Lett. 2011, 52, 5926) of the directing ability of the amide to effect selective ortho acetoxylation of 17. Similarly, Frederic Fabis of the Université de Caen Basse-Normandie used (J. Org. Chem. 2011, 76, 6414) the methoxime of 19 to direct ortho bromination, leading to 20. Teck-Peng Loh of Nanyang Technological University showed (Chem. Commun. 2011, 47, 10458) that the carbamate of 21 directed ortho C–H functionalization to give the ester 23. Yoichiro Kuninobu and Kazuhiko Takai of Okayama University rearranged (Chem. Commun. 2011, 47, 10791) the allyl ester 24 directly to the ortho-allylated acid 25. Youhong Hu of the Shanghai Institute of Materia Medica (J. Org. Chem. 2011, 76, 8495) and Graham J. Bodwell of Memorial University (J. Org. Chem. 2011, 76, 9015) condensed a chromene 26 with a nucleophile 27 to give the arene 28. C.V. Ramana of the National Chemical Laboratory prepared (Tetrahedron Lett. 2011, 52, 4627) the arene 31 by condensing 29 with 30 with high regioselectivity.

scholarly journals Resources or Capabilities: A Study of Startup Emergence within Applied Research Universities in India

2021 ◽  
Author(s):  
Kshitija Joshi ◽  
Krishna H S ◽  
Muralidharan Loganathan
Keyword(s):  
Dynamic Capabilities ◽  
Capabilities Approach ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Policy Makers ◽  
Resource Based View ◽  
Academic Environments ◽  
Intangible Resources ◽  
Start Up ◽  
Institute Of Technology

Over the past decade, the Indian entrepreneurial ecosystem has witnessed a steep growth in the number of incubators within academic environments. While most of these have focused on provision of tangible and intangible resources, the understanding about processes and routines that transform these resources into capabilities, which ultimately translate into successful start-up emergence has been lacking. Based on the resource-based view and the dynamic capabilities approach and using the cases of two academic incubators in India (Indian Institute of Technology, Madras and National Chemical Laboratory, Pune), this paper analyses the pre-incubation level processes that have resulted in their enhanced opportunity recognition potential. This study adds to the literature in the area of dynamic capabilities in the context of academic incubation. The study has important implications for both incubation setups as well as policy makers.

Stereocontrolled C-O Ring Construction: The Fuwa/Sasaki Synthesis of Attenol A

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Gold Catalysis ◽  
Membered Ring ◽  
Allylic Alcohol ◽  
State University ◽  
Prins Cyclization ◽  
University Of Florida ◽  
University Of Pittsburgh ◽  
Colorado State University ◽  
Institute Of Technology ◽  
The University

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.

Functionalization of C-H Bonds: The Baran Synthesis of Dihydroxyeudesmane

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Columbia University ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Du Bois ◽  
Rh Catalyst ◽  
Hydride Abstraction ◽  
Mcgill University ◽  
Radical Removal ◽  
The University ◽  
Useful Yield

Arumugam Sudalai of the National Chemical Laboratory, Pune reported (Tetrahedron Lett. 2008, 49, 6401) a procedure for hydrocarbon iodination. With straight chain hydrocarbons, only secondary iodination was observed. Chao-Jun Li of McGill University uncovered (Adv. Synth. Cat. 2009, 351, 353) a procedure for direct hydrocarbon amination, converting cyclohexane 1 into the amine 3. Justin Du Bois of Stanford University established (Angew. Chem. Int. Ed. 2009, 48, 4513) a procedure for alkane hydroxylation, converting 4 selectively into the alcohol 6. The oxirane 8 usually also preferentially ozidizes methines, hydroxylating steroids at the C-14 position. Ruggero Curci of the University of Bari found (Tetrahedron Lett. 2008, 49, 5614) that the substrate 7 showed some C-14 hydroxylation, but also a useful yield of the ketone 9. The authors suggested that the C-7 acetoxy group may be deactivating the C-14 C-H. C-H bonds can also be converted directly to carbon-carbon bonds. Mark E. Wood of the University of Exeter found (Tetrahedron Lett. 2009, 50, 3400) that free-radical removal of iodine from 10 followed by intramolecular H-atom abstraction in the presence of the trapping agent 11 delivered 12 with good diastereo control. Professor Li observed (Angew. Chem. Int. Ed. 2008, 47, 6278) that under Ru catalysis, hydrocarbons such as 13 could be directly arylated. He also established (Tetrahedron Lett. 2008, 49, 5601) conditions for the direct aminoalkylation of hydrocarbons such as 13, to give 17. Huw M. L. Davies of Emory University converted (Synlett 2009, 151) the ester 4 to the homologated diester 19 in preparatively useful yield using the diazo ester 18, the precursor to a selective, push-pull stabilized carbene. Intramolecular bond formation to an unactivated C-H can be even more selective. Guoshen Liu of the Shanghai Institute of Organic Chemistry developed (Organic Lett. 2009, 11, 2707) an oxidative Pd system that cyclized 20 to the seven-membered ring lactam 21 . Professor Du Bois devised (J. Am. Chem. Soc. 2008 , 130, 9220) a Rh catalyst that effected allylic amination of 22, to give 23 with substantial enantiocontrol. Dalibor Sames of Columbia University designed (J. Am. Chem. Soc. 2009, 131, 402) a remarkable cascade approach to C-H functionalization. Exposure of 24 to Lewis acid led to intramolecular hydride abstraction. Cyclization of the resulting stabilized carbocation delivered the tetrahydropyan 25 with remarkable diastereocontrol.

Other Methods for Carbocyclic Construction: The Porco Synthesis of (-)-Hyperibone K

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Oxidative Cyclization ◽  
Florida State University ◽  
State University ◽  
Colorado State University ◽  
Intramolecular Alkylation ◽  
University Of Wisconsin ◽  
Tokyo Institute ◽  
Institute Of Technology ◽  
University Of Bristol ◽  
The University

Varinder K. Aggarwal of the University of Bristol described (Angew. Chem. Int. Ed. 2010, 49, 6673) the conversion of the Sharpless-derived epoxide 1 into the cyclopropane 2. Christopher D. Bray of Queen Mary University of London established (Chem. Commun. 2010, 46, 5867) that the related conversion of 3 to 5 proceeded with high diastereocontrol. Javier Read de Alaniz of the University of California, Santa Barbara, extended (Angew. Chem. Int. Ed. 2010, 49, 9484) the Piancatelli rearrangement of a furyl carbinol 6 to allow inclusion of an amine 7, to give 8. Issa Yavari of Tarbiat Modares University described (Synlett 2010, 2293) the dimerization of 9 with an amine to give 10. Jeremy E. Wulff of the University of Victoria condensed (J. Org. Chem. 2010, 75, 6312) the dienone 11 with the commercial butadiene sulfone 12 to give the highly substituted cyclopentane 13. Robert M. Williams of Colorado State University showed (Tetrahedron Lett. 2010, 51, 6557) that the condensation of 14 with formaldehyde delivered the cyclopentanone 15 with high diastereocontrol. D. Srinivasa Reddy of Advinus Therapeutics devised (Tetrahedron Lett. 2010, 51, 5291) conditions for the tandem conjugate addition/intramolecular alkylation conversion of 16 to 17. Marie E. Krafft of Florida State University reported (Synlett 2010, 2583) a related intramolecular alkylation protocol. Takao Ikariya of the Tokyo Institute of Technology effected (J. Am. Chem. Soc. 2010, 132, 11414) the enantioselective Ru-mediated hydrogenation of bicyclic imides such as 18. This transformation worked equally well for three-, four-, five-, six-, and seven-membered rings. Stefan France of the Georgia Institute of Technology developed (Org. Lett. 2010, 12, 5684) a catalytic protocol for the homo-Nazarov rearrangement of the doubly activated cyclopropane 20 to the cyclohexanone 21. Richard P. Hsung of the University of Wisconsin effected (Org. Lett. 2010, 12, 5768) the highly diastereoselective rearrangement of the triene 22 to the cyclohexadiene 23. Strategies for polycyclic construction are also important. Sylvain Canesi of the Université de Québec devised (Org. Lett. 2010, 12, 4368) the oxidative cyclization of 24 to 25.

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