Carbon–Carbon Bond Construction: The Baran Synthesis of (+)-Chromazonarol

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Grignard Reagent ◽  
Iron Catalyst ◽  
Alkyl Halide ◽  
Titanocene Dichloride ◽  
Secondary Amide ◽  
Reductive Coupling ◽  
Quaternary Centers ◽  
Carbon Carbon Bond ◽  
The University

Daniel J. Weix of the University of Rochester effected (Org. Lett. 2012, 14, 1476) the in situ reductive coupling of an alkyl halide 2 with an acid chloride 1 to deliver the ketone 3. André B. Charette of the Université de Montréal (not illustrated) developed (Nature Chem. 2012, 4, 228) an alternative route to ketones by the coupling of an organometallic with an in situ-activated secondary amide. Mahbub Alam and Christopher Wise of the Merck, Sharpe and Dohme UK chemical process group optimized (Org. Process Res. Dev. 2012, 16, 453) the opening of an epoxide 4 with a Grignard reagent 5. Ling Song of the Fujian Institute of Research on the Structure of Matter optimized (J. Org. Chem. 2012, 77, 4645) conditions for the 1,2-addition of a Grignard reagent (not illustrated) to a readily enolizable ketone. Wei-Wei Liao of Jilin University conceived (Org. Lett. 2012, 14, 2354) of an elegant assembly of highly functionalized quaternary centers, as illustrated by the conversion of 7 to 8. Antonio Rosales of the University of Granada and Ignacio Rodríguez-García of the University of Almería prepared (J. Org. Chem. 2012, 77, 4171) free radicals by reduction of an ozonide 9 in the presence of catalytic titanocene dichloride. In the absence of the acceptor 10, the dimer of the radical was obtained, presenting a simple alternative to the classic Kolbe coupling. Marc L. Snapper of Boston College found (Eur. J. Org. Chem. 2012, 2308) that the difficult ketone 12 could be methylenated following a modified Peterson protocol. Yoshito Kishi of Harvard University optimized (Org. Lett. 2012, 14, 86) the coupling of 15 with 16 to give 17. Masaharu Nakamura of Kyoto University devised (J. Org. Chem. 2012, 77, 1168) an iron catalyst for the coupling of 18 with 19. The specific preparation of trisubsituted alkenes is an ongoing challenge. Quanri Wang of Fudan University and Andreas Goeke of Givaudan Shanghai fragmented (Angew. Chem. Int. Ed. 2012, 51, 5647) the ketone 21 by exposure to 22 to give the macrolide 23 with high stereocontrol.

Carbon–Carbon Bond Construction

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Organic Synthesis ◽  
Grignard Reagent ◽  
Secondary Amide ◽  
State University ◽  
Wayne State University ◽  
Carbon Carbon Bond ◽  
Diazo Ketone ◽  
Peking University ◽  
Subsequent Exposure ◽  
The University

Carlo Siciliano and Angelo Liguori of the Università della Calabria showed (J. Org. Chem. 2012, 77, 10575) that an amino acid 1 could be both protected and activated with Fmoc-Cl, so subsequent exposure to diazomethane delivered the Fmoc-protected diazo ketone 2. Pei-Qiang Huang of Xiamen University activated (Angew. Chem. Int. Ed. 2012, 51, 8314) a secondary amide 3 with triflic anhydride, then added an alkyl Grignard reagent with CeCl3 to give an intermediate that was reduced to the amine 4. John C. Walton of the University of St. Andrews found (J. Am. Chem. Soc. 2012, 134, 13580) that under irradiation, titania could effect the decarboxylation of an acid 5 to give the dimer 6. Jin Kun Cha of Wayne State University demonstrated (Angew. Chem. Int. Ed. 2012, 51, 9517) that a zinc homoenolate derived from 7 could be transmetalated, then coupled with an electrophile to give the alkylated product 8. The Ramberg-Bäcklund reaction is an underdeveloped method for the construction of alkenes. Adrian L. Schwan of the University of Guelph showed (J. Org. Chem. 2012, 77, 10978) that 10 is a particularly effective brominating agent for this transformation. Daniel J. Weix of the University of Rochester coupled (J. Org. Chem. 2012, 77, 9989) the bromide 12 with the allylic carbonate 13 to give 14. The Julia-Kocienski coupling, illustrated by the addition of the anion of 16 to the aldehyde 15, has become a workhorse of organic synthesis. In general, this reaction is E selective. Jirí Pospísil of the University Catholique de Louvain demonstrated (J. Org. Chem. 2012, 77, 6358) that inclusion of a K+-sequestering agent switched the selectivity to Z. Yoichiro Kuninobu, now at the University of Tokyo, and Kazuhiko Takai of Okayama University constructed (Org. Lett. 2012, 14, 6116) the tetrasubstituted alkene 20 with high geometric control by the Re-catalyzed addition of 19 to the alkyne 18. André B. Charette of the Université de Montréal converted (Org. Lett. 2012, 14, 5464) the allylic halide 21 to the alkyne 22 by displacement with iodoform followed by elimination. In an elegant extension of his studies with alkyl tosylhydrazones, Jianbo Wang of Peking University added (J. Am. Chem. Soc. 2012, 134, 5742) an alkyne 24 to 23 to give 25.

Carbon–Carbon Bond Formation: The Bergman Synthesis of (+)-Fuligocandin B

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Grignard Reagent ◽  
Alkyl Halide ◽  
Secondary Alcohol ◽  
Ni Catalyst ◽  
West Virginia University ◽  
Carbon Carbon Bond ◽  
Peking University ◽  
National University ◽  
The University ◽  
École Polytechnique

Xile Hu of the Ecole Polytechnique Fédérale de Lausanne optimized (J. Am. Chem. Soc. 2011, 133, 7084) a Ni catalyst for the coupling of a Grignard reagent 2 with a secondary alkyl halide 1. Duk Keun An of Kangwon National University devised (Tetrahedron Lett. 2011, 52, 1718; Chem. Commun. 2011, 47, 3281) a strategy for the reductive coupling of an ester 4 with a Grignard reagent 2 to give the secondary alcohol. Daniel J. Weix of the University of Rochester added (Org. Lett. 2011, 13, 2766) the halide 7 in a conjugate sense to the bromoenone 6, setting the stage for further organometallic coupling. James Y. Becker of the Ben-Gurion University of the Negev effected (J. Org. Chem. 2011, 76, 4710) Kolbe coupling of the silyl acid 9 to give the decarboxylated dimer 10. Shi-Kai Tian of USTC Hefei showed (Chem. Commun. 2011, 47, 2158) that depending on the sulfonyl group used, the coupling of 11 with 12 could be directed cleanly toward either the Z or the E product. Yoichiro Kuninobu and Kazuhiko Takai of Okayama University added (Org. Lett. 2011, 13, 2959) the sulfonyl ketone 14 to the alkyne 13 to form the trisubstituted alkene 15. Jianbo Wang of Peking University assembled (Angew. Chem. Int. Ed. 2011, 50, 3510) the trisubstituted alkene 18 by adding the diazo ester 16 to the alkyne 17. Gangguo Zhu of Zhejiang Normal University constructed (J. Org. Chem. 2011, 76, 4071) the versatile tetrasubstituted alkene 21 by adding the chloroalkyne 19 to acrolein 20. Other more substituted acceptors worked as well. Chunxiang Kuang of Tongji University and Qing Yang of Fudan University effected (Tetrahedron Lett. 2011, 52, 992) elimination of 22 to 23 by stirring with Cs2CO3 at 115°C in DMSO overnight. Toshiaki Murai of Gifu University created (Chem. Lett. 2011, 40, 70) a propargyl anion by condensing 24 with 25 then adding 26. Xiaodong Shi of West Virginia University found (Org. Lett. 2011, 13, 2618) that the enantiomerically enriched propargyl ether 29 could be rearranged to the trisubsituted allene 30 with retention of the ee and with high de.

Carbon-Carbon Bond Formation

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Alkyl Halide ◽  
Bond Formation ◽  
Conjugate Addition ◽  
Phenyl Isocyanate ◽  
Ni Catalyst ◽  
Reductive Coupling ◽  
Carbon Carbon Bond ◽  
University Of Technology ◽  
Osaka Prefecture ◽  
The University

Akiya Ogawa of Osaka Prefecture University found (Tetrahedron Lett. 2010, 51, 6580) that the Sm-mediated reductive coupling of a halide 1 with CO2 to give the carboxylic acid 2 was strongly promoted by visible light. Gregory C. Fu of MIT designed (Angew. Chem. Int. Ed. 2010, 49, 6676) a Ni catalyst for the coupling of a primary borane 4 with a secondary alkyl halide 3. James P. Morken of Boston College devised (Org. Lett. 2010, 12, 3760) conditions for the carbonylative conjugate addition of a dialkyl zinc to an enone 6 to give the 1,4-dicarbonyl product 7. Louis Fensterbank of the Institut Parisien de Chimie Moléculaire developed (Angew. Chem. Int. Ed. 2010, 49, 8721; not illustrated) a protocol for the conjugate addition of alkyl boranes to enones. Hyunik Shin of LG Life Science, Daejeon, and Sang-gi Lee of Ewha Womans University showed (Tetrahedron Lett. 2010, 51, 6893) that the intermediate from Blaise homologation of a nitrile 8 was a powerful nucleophile, smoothly opening an epoxide 10 to deliver 11. Sébastien Reymond and Janine Cossy of ESPCI ParisTech found (J. Org. Chem. 2010, 75, 5151) that FeCl3 smoothly catalyzed the coupling of an alkenyl Grignard 13 with the primary iodide 12. The Ti-mediated coupling of an alkyne 16 with an allylic alkoxide 15 (J. Am. Chem. Soc. 2010, 132, 9576) developed by Glenn C. Micalizio of Scripps/Florida was the key step in the total synthesis (J. Am. Chem. Soc. 2010, 132, 11422) of lehualide B. Huanfeng Jiang of the South China University of Technology observed (Chem. Commun. 2010, 46, 8049) that KI added to a bromoalkyne 18 to give the dihalide 19 with high geometric control. Haruhiko Fuwa of Tohoku University improved (Org. Lett. 2010, 12, 5354) the selective hydroiodination of a methyl alkyne 20 to 21. Takuya Kurahashi and Seijiro Matsubara of Kyoto University devised (Chem. Commun. 2010, 46, 8055) the Ni-catalyzed three-component coupling of an alkyne 22, methyl acrylate 23, and phenyl isocyanate to give the doubly homologated lactam 24. Patrick H. Toy of the University of Hong Kong showed (Synlett 2010, 1997; Org. Lett. 2010, 12, 4996 for a polymer with covalently attached base) that resin-bound triphenylphosphine participated efficiently in the Wittig coupling of 26 with an aldehyde 25.

Reactions of Alkenes

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Catalytic Reduction ◽  
Indian Institute ◽  
Yale University ◽  
Terminal Alkene ◽  
National University ◽  
Institute Of Technology ◽  
La Jolla ◽  
The University

The catalytic reduction of the alkene 1 gave the cis-fused product (not illustrated), by kinetic H₂ addition to the less congested face of the alkene. Ryan A. Shenvi of Scripps La Jolla found (J. Am. Chem. Soc. 2014, 136, 1300) conditions for stepwise HAT, con­verting 1 to the thermodynamically-favored trans-fused ketone 2. Seth B. Herzon of Yale University devised (J. Am. Chem. Soc. 2014, 136, 6884) a protocol for the reduc­tion, mediated by 4, of the double bond of a haloalkene 3 to give the saturated halide 5. The Shenvi conditions also reduced a haloalkene to the saturated halide. Daniel J. Weix of the University of Rochester and Patrick L. Holland, also of Yale University, established (J. Am. Chem. Soc. 2014, 136, 945) conditions for the kinetic isomerization of a terminal alkene 6 to the Z internal alkene 7. Christoforos G. Kokotos of the University of Athens showed (J. Org. Chem. 2014, 79, 4270) that the ketone 9, used catalytically, markedly accelerated the Payne epoxidation of 8 to 10. Note that Helena M. C. Ferraz of the Universidade of São Paulo reported (Tetrahedron Lett. 2000, 41, 5021) several years ago that alkene epoxidation was also easily carried out with DMDO generated in situ from acetone and oxone. Theodore A. Betley of Harvard University prepared (Chem. Sci. 2014, 5, 1526) the allylic amine 12 by reacting the alkene 11 with 1-azidoadamantane in the presence of an iron catalyst. Rodney A. Fernandes of the Indian Institute of Technology Bombay developed (J. Org. Chem. 2014, 79, 5787) efficient conditions for the Wacker oxida­tion of a terminal alkene 6 to the methyl ketone 13. Yong-Qiang Wang of Northwest University oxidized (Org. Lett. 2014, 16, 1610) the alkene 6 to the enone 14. Peili Teo of the National University of Singapore devised (Chem. Commun. 2014, 50, 2608) conditions for the Markovnikov hydration of the alkene 6 to the alcohol 15. Internal alkenes were inert under these conditions, but Yoshikazo Kitano of the Tokyo University of Agriculture and Technology effected (Synthesis 2014, 46, 1455) the Markovnikov amination (not illustrated) of more highly substituted alkenes.

Functional Group Interconversion

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Ruthenium Complex ◽  
Cross Coupling ◽  
Allylic Alcohol ◽  
Secondary Amide ◽  
University Of Delaware ◽  
Weizmann Institute ◽  
Yale University ◽  
In Situ Generation ◽  
The University

David Milstein at the Weizmann Institute of Science reported (Angew. Chem. Int. Ed. 2013, 52, 6269) the unusual deamination of amine 1 to alcohol 3 catalyzed by ruthenium complex 2. In the reverse sense, Qing Xu at Wenzhou University found (Adv. Synth. Cat. 2013, 355, 73) that the conversion of benzyl alcohol (4) to sulfonamide 5 was catalyzed by benzaldehyde and catalytic potassium carbonate. Gold(I) catalysis was utilized (Chem. Commun. 2013, 49, 4262) by Ai-Lan Lee at Heriot-Watt University for the direct etherification of allylic alcohol 6 with isopropanol to produce 7. Tobias Ritter at Harvard demonstrated (J. Am. Chem. Soc. 2013, 135, 2470) that the reagent PhenoFluor (9) developed in his laboratory displays astonishing selectivity for the late-stage deoxyfluorination of complex alcohols and polyols, including glucopyranoside 8 to produce 10. A Mitsunobu protocol for the conversion of alcohol 11 to ester 13 using catalytic amounts of the hydrazide 12 and iron(II) phthalocyanine was developed (Angew. Chem. Int. Ed. 2013, 52, 4613) by Tsuyoshi Taniguchi at Kanazawa University. We reported (Org. Lett. 2013, 15, 38) a Mitsunobu-like inversion of alcohol 14 to mesylate 16 catalyzed by diphenylcyclopropenone 15. Domingo Gomez Pardo and Janine Cossy at ESPCI Paris Tech found (Org. Lett. 2013, 15, 902) that the reagent XtalFluor-E (18) was effective for the coupling of N-Boc proline (17) and phenylglycine ethyl ester (19) without epimerization to furnish the dipeptide 20. The conversion of primary amide 21 to secondary amide 23 via cross-coupling with boronic acid 22 was reported (Org. Lett. 2013, 15, 2314) by Donald A. Watson at the University of Delaware. Catalysis of the Lossen rearrangement of hydroxamide 24 to carbamate 26 using N-methylimidazole (25), which helped to minimize side products, was reported (Org. Lett. 2013, 15, 602) by Scott J. Miller at Yale University. Keiji Maruoka at Kyoto University demonstrated (Angew. Chem. Int. Ed. 2013, 52, 5532) that propionaldehyde (27) could be converted under simple conditions to N-Boc aminal 28, which served as a convenient source for the in situ generation of the corresponding highly useful N-Boc imine.

New Methods for Carbon-Carbon Bond Construction

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Allylic Alcohol ◽  
Ni Catalyst ◽  
University Of Michigan ◽  
Carbon Carbon Bond ◽  
University Of Technology ◽  
Duke University ◽  
Michael Acceptors ◽  
Leaving Groups ◽  
The University

Mohammad Navid Soltani Rad of Shiraz University of Technology has shown (Tetrahedron Lett. 2007, 48, 6779) that with tosylimidazole (TsIm) activation in the presence of NaCN, primary, secondary and tertiary alcohols are converted into the corresponding nitriles. Gregory C. Fu of MIT has devised (J. Am. Chem. Soc. 2007, 129, 9602) a Ni catalyst that mediated the coupling of sp3-hybridized halides such as 3 with sp3-hybridized organoboranes such as 4, to give 5. Usually, carbanions with good leaving groups in the beta position do not couple efficiently, but just eliminate. Scott D. Rychnovsky of the University of California, Irvine has found (Organic Lett . 2007, 9, 4757) that initial protection of 6 as the alkoxide allowed smooth reduction of the sulfide and addition of the derived alkyl lithium to the amide 7 to give 8. Doubly-activated Michael acceptors such as 11 are often too unstable to isolate. J. S. Yadav of the Indian Institute of Chemical Technology, Hyderabad has shown (Tetrahedron Lett. 2007, 48, 7546) that Baylis-Hillman adducts such as 9 can be oxidized in situ, with concomitant Sakurai addition to give 12. Rather than use the usual Li or Na or K enolate, Don M. Coltart of Duke University has found (Organic Lett. 2007, 9, 4139) that ketones such as 13 will condense with amides such as 14 to give the diketone 15 on exposure to MgBr2. OEt2 and i -Pr2 NEt. Simultaneously, Gérard Cahiez of the Université de Cergy (Organic Lett. 2007, 9, 3253) and Janine Cossy of ESPCI Paris (Angew. Chem. Int. Ed. 2007, 46, 6521) reported that Fe salts will catalyze the coupling of sp2 -hybridized Grignard reagents such as 17 with alkyl halides. John Montgomery of the University of Michigan has described (J. Am. Chem. Soc. 2007, 129, 9568) the Ni-mediated regio- and enantioselective addition of an alkynes 20 to an aldehyde 19 to give the allylic alcohol 21. In a third example of sp2 - sp3 coupling, Troels Skrydstrup of the University of Aarhus has established (J. Org. Chem. 2007, 72, 6464) that Negishi coupling with alkenyl phosponates such as 23 proceeded efficiently.

Metal-Mediated Carbocyclic Construction: The Whitby Synthesis of (+)-Mucosin

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Fischer Carbene ◽  
Heck Cyclization ◽  
Peking University ◽  
Rh Catalyst ◽  
Tokyo Institute ◽  
Hydride Elimination ◽  
Institute Of Technology ◽  
The University

Erick M. Carreira of ETH-Zürich generated (Org. Lett. 2012, 14, 2162) ethyl diazoacetate in situ in the presence of the alkene 1 and an iron catalyst to give the cyclopropane 3. Joseph M. Fox of the University of Delaware inserted (Chem. Sci. 2012, 3, 1589) the Rh carbene derived from 5 into the alkene 4 to give the cyclopropene 6, without β-hydride elimination. Masaatsu Adachi and Toshio Nishikawa of Nagoya University reduced (Chem. Lett. 2012, 41, 287) the enone 7 to give the cyclobutanol 8. Intramolecular ketene cycloaddition has been limited to very electron-rich acceptor alkenes. Xiao-Ping Cao and Yong-Qiang Tu of Lanzhou University devised (Chem. Sci. 2012, 3, 1975) a protocol that converted 9 into the cyclobutanone 10 with high diastereocontrol. The intermediate is the tosylhydrazone of the ketone, so a reductive workup would lead to the corresponding cycloalkane. Koichi Mikami of the Tokyo Institute of Technology added (J. Am. Chem. Soc. 2012, 134, 10329) alkyl cuprates to the prochiral enone 11 to give the enolate trapping product 13 in high ee and with high diastereocontrol. Marcus A. Tius of the University of Hawaii found (Angew. Chem. Int. Ed. 2012, 51, 5727) a Pd catalyst for the Nazarov cyclization of 14 to 15. Antoni Riera and Xavier Verdaguer of the Universitat de Barcelona prepared (Org. Lett. 2012, 14, 3534) 16 by enantioselective Pauson-Khand addition to tetramethyl norbornadiene. Conjugate addition followed by retro Diels-Alder could potentially lead to the cyclopentenone 17. The intermolecular Pauson-Khand cyclization often gives mixtures of regioisomers. José Barluenga of the Universidad de Oviedo demonstrated (Angew. Chem. Int. Ed. 2012, 51, 183) an alternative, the addition of an alkenyl lithium 19 to the Fischer carbene 18 leading to 20. Jian-Hua Xie and Qi-Lin Zhou of Nankai University hydrogenated (Adv. Synth. Catal. 2012, 354, 1105; see also Org. Lett. 2012, 14, 2714) the ketone 21 under epimerizing conditions to give the alcohol 22. Kozo Shishido of the University of Tokushima observed (Tetrahedron Lett. 2012, 53, 145) that the intramolecular Heck cyclization of 23 proceeded with high diastereocontrol. Zhi-Xiang Yu of Peking University devised (Org. Lett. 2012, 14, 692) an Rh catalyst for the cyclocarbonylation of 25 to 26.

Carbon–Carbon Bond Formation: The Petrov Synthesis of Combretastatin A-4

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Good Control ◽  
Geometric Control ◽  
Pt Catalyst ◽  
University Of Mississippi ◽  
Santa Barbara ◽  
University Of Illinois ◽  
University Of Alberta ◽  
Carbon Carbon Bond ◽  
The University

Janine Cossy of ESPCI Paris (Org. Lett. 2011, 13, 4084) and Yasushi Obora of Kansai University (Chem. Lett. 2011, 40, 1055) independently developed conditions for the “borrowed hydrogen” condensation of acetonitrile with an alcohol 1 to give the nitrile 2. Akio Baba of Osaka University showed (Angew. Chem. Int. Ed. 2011, 50, 8623) that a ketene silyl acetal 4 could be condensed with a carboxylic acid 3 to give the β-keto ester 5. Timothy W. Funk of Gettysburg College found (Tetrahedron Lett. 2010, 51, 6726) that the cyclopropanol 6, readily prepared by Kulinkovich condensation of an alkene with an ester, opened with high regioselectivity to give the branched ketone 7. In an elegant application of C–H functionalization, Yong Hae Kim of KAIST and Kieseung Lee of Woosuk University added (Tetrahedron Lett. 2011, 52, 4662) the acetal 9 in a conjugate sense to 8 to give 10. Hitoshi Kuniyasu and Nobuaki Kambe of Osaka University devised (Tetrahedron Lett. 2010, 51, 6818) conditions for the Pd-catalyzed carbonylation of a silyl alkyne 11 to the ester 12 with high geometric control. Dennis G. Hall of the University of Alberta also observed (Chem. Sci. 2011, 2, 1305) good geometric control in the rearrangement of the vinyl carbinol 13 to the alcohol 14. Takashi Tomioka of the University of Mississippi condensed (J. Org. Chem. 2011, 76, 8053) the anion 16, prepared in situ from lithio acetonitrile and 1-iodobutane, with the aldehyde 15 to give a nitrile, which was carried onto the aldehyde 17, again with good control of geometry. Bruce H. Lipshutz of the University of California, Santa Barbara established (Org. Lett. 2011, 13, 3818) conditions for the Negishi coupling of an alkenyl halide 18 to give 20 with retention of alkene geometry. Daesung Lee of the University of Illinois, Chicago found (J. Am. Chem. Soc. 2011, 133, 12964) that a Pt catalyst rearranged a silyl cyclopropene 21 to the allene 22. Jan Deska of the Universität zu Köln prepared (Angew. Chem. Int. Ed. 2011, 50, 9731) the enantiomerically enriched allene 25 by lipase-mediated esterification of the prochiral 23.

C–H Functionalization: The Ono/Kato/Dairi Synthesis of Fusiocca-1,10(14)-diene-3,8β,16-triol

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Cytochrome P450 ◽  
Iron Catalyst ◽  
State University ◽  
Colorado State University ◽  
Carbon Carbon Bond ◽  
National University ◽  
Rh Catalyst ◽  
Hydride Abstraction ◽  
Osaka Prefecture ◽  
The University

Theodore A. Betley of Harvard University devised (J. Am. Chem. Soc. 2011, 133, 4917) an iron catalyst for inserting the nitrene from 2 into the C–H of 1 to give 3. Bernhard Breit of the Freiburg Institute for Advanced Studies uncovered (J. Am. Chem. Soc. 2011, 133, 2386) a Rh catalyst that effected the intriguing hydration of a terminal alkyne 4 to the allylic ester 5. Yian Shi of Colorado State University specifically oxidized (Org. Lett. 2011, 13, 1548) one of the two allylic sites of 6 to give 7. Kálmán J. Szabó of Stockholm University optimized (J. Org. Chem. 2011, 76, 1503) the allylic oxidation of 9 to 10, using the inexpensive sodium perborate. Masayuki Inoue of the University of Tokyo specifically carbamoylated (Tetrahedron Lett. 2011, 52, 2885) the acetonide 12 to give 14. Stephen Caddick of University College London added (Tetrahedron Lett. 2011, 52, 1067) the formyl radical from 15 to 16 to give 17. Ilhyong Ryu of Osaka Prefecture University and Maurizio Fagnoni of the University of Pavia employed (Angew. Chem. Int. Ed. 2011, 50, 1869) a related strategy to effect the net transformation of 18 to 20. There are many examples of the oxidation of ethers and amines to reactive intermediates that can go on to carbon–carbon bond formation. Ram A. Vishwakarma of the Indian Institute of Integrative Medicine observed (Chem. Commun. 2011, 47, 5852) that with an iron catalyst, the aryl Grignard 22 smoothly coupled with THF 21 to give 23. Gong Chen of Pennsylvania State University effected (Angew. Chem. Int. Ed. 2011, 50, 5192) specific remote C–H arylation of 24, leading to 26. Takahiko Akiyama of Gakushuin University established (J. Am. Chem. Soc. 2011, 133, 2424) conditions for intramolecular hydride abstraction, effecting the conversion of 27 to 28. C–H functionalization in nature is often mediated by cytochrome P450 oxidation. Zhi Li of the National University of Singapore showed (Chem. Commun. 2011, 47, 3284) that a particular cytochrome P450 selectively oxidized 29 to the alcohol 30, leaving the chemically more reactive benzylic position intact.

C–C Bond Construction: The Galano Synthesis of 8-F3t-Isoprostane

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Carbon Monoxide ◽  
Grignard Reagent ◽  
Alkyl Halide ◽  
Boston College ◽  
Pinacol Rearrangement ◽  
Alpha Olefin ◽  
Osaka Prefecture ◽  
The University ◽  
École Polytechnique

Nobuaki Kambe of Osaka University devised (Synthesis 2014, 46, 1583) simple con­ditions for coupling an alkyl halide 1 with a Grignard reagent 2, leading to 3. Michael J. Chetcuti and Vincent Ritleng of the Université de Strasbourg arylated (Chem. Commun. 2014, 50, 4624) the ketone 4 with 5 to give 6. Ilhyong Ryu of Osaka Prefecture University effected (J. Org. Chem. 2014, 79, 3999) net conjugate acylation of the enone 8 to give 9 by reducing 7 in the presence of carbon monoxide. Yasushi Obora of Kansai University employed (Chem. Commun. 2014, 50, 2491) a borrowed hydrogen strategy to effect the net methylation of 10 to 11. There have been many examples of the alkylation of ketones using variations on this strategy. Robert H. Grubbs and Brian M. Stoltz of Caltech decarboxylated (Adv. Synth. Catal. 2014, 356, 130) an acid 12 to the corresponding alpha olefin 13. Lindsey O. Davis of Berry College combined (Tetrahedron Lett. 2014, 55, 3100) the imine 14 with the aldehyde 15 in the presence of 16 to give the enone 17. Masahiro Miyazawa of the University of Toyoma maintained (Synlett 2014, 25, 531) the geometric purity of 18 while coupling it with Me₃Al to give the diene 19. Naoki Kanoh of Tohoku University used (Eur. J. Org. Chem. 2014, 1376) the Micalizio protocol to add 22 with 21 to 20 to give the triene 23. Xile Hu of the Ecole Polytechnique Fédérale de Lausanne coupled (Org. Lett. 2014, 16, 2566) 25 with the iodide 24 to give the alkyne 26. Keiji Tanino of Hokkaido University prepared (Tetrahedron Lett. 2014, 55, 1097) the α-quaternary alkyne 29 by 1,2-addition of 28 to the ketone 27 followed by pinacol rearrangement. Zhaoguo Zhang of Shanghai Jiao Tong University and Tahar Ayad and Virginie Ratovelomanana-Vidal of Chimie ParisTech coupled (ACS Catal. 2014, 4, 44) 31 with the dienyl bromide 30 to deliver the disubstituted allene 32 in high ee. Amir H. Hoveyda of Boston College developed (Angew. Chem. Int. Ed. 2013, 52, 7694) a procedure for the preparation of alkynes such as 33 in substantial ee.

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