Reactions of Alkenes: The RajanBabu Synthesis of Pseudopterosin G-J Aglycone Dimethyl Ether

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Medical Center ◽  
Selective Reduction ◽  
Oxidative Cleavage ◽  
University Of Texas ◽  
Furman University ◽  
National University ◽  
Institute Of Technology ◽  
Seoul National University ◽  
The University ◽  
Medical University

Xiangge Zhou of Sichuan University showed (Tetrahedron Lett. 2011, 52, 318) that even the monosubstituted alkene 1 was smoothly converted to the methyl ether 2 by catalytic FeCl3. Brian C. Goess of Furman University protected (J. Org. Chem. 2011, 76, 4132) the more reactive alkene of 3 as the 9-BBN adduct, allowing selective reduction of the less reactive alkene to give, after reoxidation, the monoreduced 4. Nobukazu Taniguchi of the Fukushima Medical University added (Synlett 2011, 1308) Na p-toluenesulfinate oxidatively to 1 to give the sulfone 5. Krishnacharya G. Akamanchi of the Indian Institute of Chemical Technology, Mumbai oxidized (Synlett 2011, 81) 1 directly to the bromo ketone 6. Osmium is used catalytically both to effect dihydroxylation, to prepare 8, and to mediate oxidative cleavage, as in the conversion of 7 to the dialdehyde 9. Ken-ichi Fujita of AIST Tsukuba devised (Tetrahedron Lett. 2011, 52, 3137) magnetically retrievable osmium nanoparticles that can be reused repeatedly for the dihydroxylation. B. Moon Kim of Seoul National University established (Tetrahedron Lett. 2011, 52, 1363) an extraction scheme that allowed the catalytic Os to be reused repeatedly for the oxidative cleavage. Maurizio Taddei of the Università di Siena showed (Synlett 2011, 199) that aqueous formaldehyde could be used in place of Co/H2 (syngas) for the formylation of 1 to 10. Hirohisa Ohmiya and Masaya Sawamura of Hokkaido University prepared (Org. Lett. 2011, 13, 1086) carboxylic acids (not illustrated) from alkenes using CO2. Joseph M. Ready of the University of Texas Southwestern Medical Center selectively arylated (Angew. Chem. Int. Ed. 2011, 50, 2111) the homoallylic alcohol 11 to give 12. Many reactions of alkenes are initiated by hydroboration, then conversion of the resulting alkyl borane. Hiroyuki Kusama of the Tokyo Institute of Technology photolyzed (J. Am. Chem. Soc. 2011, 133, 3716) 14 with 13 to give the ketone 15. William G. Ogilvie of the University of Ottawa added (Synlett 2011, 1113) the 9-BBN adduct from 1 to 16 to give 17. Professors Ohmiya and Sawamura effected (Org. Lett. 2011, 13, 482) a similar conjugate addition, not illustrated, of 9-BBN adducts to α,β-unsaturated acyl imidazoles.

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.

Construction of Alkylated Stereogenic Centers

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Phase Transfer ◽  
Conjugate Addition ◽  
Enantioselective Hydrogenation ◽  
Boronic Acids ◽  
National University ◽  
Cu Catalyst ◽  
Institute Of Technology ◽  
Enantioselective Alkylation ◽  
Seoul National University ◽  
The University

Andreas Pfaltz of the University of Basel and Keisuke Suzuki of the Tokyo Institute of Technology showed (Angew. Chem. Int. Ed. 2010, 49, 881) that the iodohydrin of 1 did not interfere with the enantioselective hydrogenation. J. R. Falck of UT Southwestern developed (J. Am. Chem. Soc. 2010, 132, 2424) a procedure for coupling arene boronic acids with a cyano triflate 3, readily available in high ee from the corresponding aldehyde. Anita R. Maguire of University College Cork devised (J. Am. Chem. Soc. 2010, 132, 1184) a Cu catalyst for the enantioselective C-H insertion cyclization of 5 to 6. Jin-Quan Yu of Scripps/La Jolla established (J. Am. Chem. Soc. 2010, 132, 460) a complementary enantioselective C-H functionalization protocol, converting the prochiral 7 into 8 in high ee. Xumu Zhang of Rutgers University effected (Angew. Chem. Int. Ed. 2010, 49, 4047) enantioselective branching hydroformylation of 9 to give 10. T. V. RajanBabu of Ohio State University established (J. Am. Chem. Soc. 2010, 132, 3295) the enantioselective hydrovinylation of a diene 11 to the diene 12. Gregory C. Fu extended (J. Am. Chem. Soc. 2010, 132, 1264, 5010) Ni-mediated cross-coupling, both with alkenyl and aryl nucleophiles, to the racemic bromoketone 13. Hyeung-geun Park and Sang-sup Jew of Seoul National University used (Organic Lett. 2010, 12 , 2826) their asymmetric phase transfer protocol to effect the enantioselective alkylation of the amide 15. Kyung Woon Jung of the University of Southern California showed (J. Org. Chem. 2010, 75, 95) that the oxidative Pd-mediated Heck coupling of arene boronic acids to 17 could be effected in high ee. Nicolai Cramer of ETH Zurich observed (J. Am. Chem. Soc. 2010, 132, 5340) high enantioinduction in the cleavage of the prochiral cyclobutanol 19. Alexandre Alexakis of the University of Geneva achieved (Organic Lett. 2010, 12, 1988) the long-sought goal of efficient enantioselective conjugate addition of a Grignard reagent to an unsaturated aldehyde 21. Professor Alexakis also established (Organic Lett. 2010, 12, 2770) conditions for enantioselective conjugate addition to a nitrodiene 23. This procedure worked equally well for β-alkynyl nitroalkenes.

Enantioselective Construction of Alkylated Centers: The Shishido Synthesis of (+)-Helianane

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Allylic Alcohol ◽  
National University ◽  
Cu Catalyst ◽  
Rh Catalyst ◽  
Enantioselective Acylation ◽  
Enantioselective Addition ◽  
Institute Of Technology ◽  
Enantioselective Alkylation ◽  
Seoul National University ◽  
The University

Teck-Peng Loh of Nanyang Technological University developed (Org. Lett. 2011, 13, 876) a catalyst for the enantioselective addition of an aldehyde to the versatile acceptor 2 to give 3. Kirsten Zeitler of the Universität Regensburg employed (Angew. Chem. Int. Ed. 2011, 50, 951) a complementary strategy for the enantioselective coupling of 4 with 5. Clark R. Landis of the University of Wisconsin devised (Org. Lett. 2011, 13, 164) an Rh catalyst for the enantioselective formylation of the diene 7. Don M. Coltart of Duke University alkylated (J. Am. Chem. Soc. 2011, 133, 8714) the chiral hydrazone of acetone to give 9, then alkylated again to give, after hydrolysis, the ketone 11 in high ee. Youming Wang and Zhenghong Zhou of Nankai University effected (J. Org. Chem. 2011, 76, 3872) the enantioselective addition of acetone to the nitroalkene 12. Takeshi Ohkuma of Hokkaido University achieved (Angew. Chem. Int. Ed. 2011, 50, 5541) high ee in the Ru-catalyzed hydrocyanation of 15. Gregory C. Fu, now at the California Institute of Technology, coupled (J. Am. Chem. Soc. 2011, 133, 8154) the 9-BBN borane 18 with the racemic chloride 17 to give 19 in high ee. Scott McN. Sieburth of Temple University optimized (Org. Lett. 2011, 13, 1787) an Rh catalyst for the enantioselective intramolecular hydrosilylation of 20 to 21. Several general methods have been devised for the enantioselective assembly of quaternary alkylated centers. Sung Ho Kang of KAIST Daejon developed (J. Am. Chem. Soc. 2011, 133, 1772) a Cu catalyst for the enantioselective acylation of the prochiral diol 22. Hyeung-geun Park of Seoul National University established (J. Am. Chem. Soc. 2011, 133, 4924) a phase transfer catalyst for the enantioselective alkylation of 24. Peter R. Schreiner of Justus-Liebig University Giessen found (J. Am. Chem. Soc. 2011, 133, 7624) a silicon catalyst that efficiently rearranged the Shi-derived epoxide of 26 to the aldehyde 27. Amir H. Hoveyda of Boston College coupled (J. Am. Chem. Soc. 2011, 133, 4778) 28 with the alkynyl Al reagent 29 to give 30 in high ee. Kozo Shishido of the University of Tokushima prepared (Synlett 2011, 1171) 31 by the Mitsunobu coupling of m-cresol with the enantiomerically pure allylic alcohol.

Construction of Single Stereocenters

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Medical Center ◽  
Columbia University ◽  
Santa Barbara ◽  
Electrophilic Amination ◽  
Ene Reaction ◽  
University Of Texas ◽  
University Of Wisconsin ◽  
Nucleophilic Displacement ◽  
Institute Of Technology ◽  
The University

James L. Leighton at Columbia University reported (Nature 2012, 487, 86) that the commercially available allylsilane 2 allylated acetoacetone (1) to furnish the enantioenriched tertiary carbinol 3. Alexander T. Radosevich demonstrated (Angew. Chem. Int. Ed. 2012, 51, 10605) that diazaphospholidine 5 induced the formal reductive insertion of 3,5-dinitrobenzoic acid to α-ketoester 4 to generate adduct 6 enantioselectively. Tehshik P. Yoon at the University of Wisconsin at Madison found (J. Am Chem. Soc. 2012, 134, 12370) that aminoalcohol derivative 9 could be prepared via an asymmetric iron-catalyzed oxyamination of diene 7 using oxaziridine 8. A procedure for the desymmetrization of 1,3-difluoropropanol 10 by nucleophilic displacement of an unactivated aliphatic fluoride to generate 11 was reported (Angew. Chem. Int. Ed. 2012, 51, 12275) by Günter Haufe at the University of Münster and Norio Shibata at the Nagoya Institute of Technology. An innovative procedure for the amination of unactivated olefins involving an ene reaction/[ 2,3]-rearrangement sequence (e.g., 12 to 13) was developed (J. Am. Chem. Soc. 2012, 134, 18495) by Uttam K. Tambar at the University of Texas Southwestern Medical Center. James P. Morken at Boston College demonstrated the stereospecific amination of borane 14 with methoxylamine to produce 15. The conversion of β-ketoester 16 to 18 by amination with 17 under oxidative conditions was reported (J. Am. Chem. Soc. 2012, 134, 18948) by Javier Read de Alaniz at the University of California at Santa Barbara. The electrophilic amination of silyl ketene acetal 19 with a functionalized hydroxylamine reagent to produce 20 was disclosed (Angew. Chem. Int. Ed. 2012, 51, 11827) by Koji Hirano and Masahiro Miura at Osaka University. Erick M. Carreira at ETH Zürich developed (Angew. Chem. Int. Ed. 2012, 51, 8652) the enantioconvergent thioetherification of alcohol 21 to produce 23 with high branched to linear selectivity and ee. The asymmetric conjugate addition of 2-aminothiophenol 25 to 24 catalyzed by mesitylcopper in the presence of ligand 26 was developed (Angew. Chem. Int. Ed. 2012, 51, 8551) by Naoya Kumagai and Masakatsu Shibasaki at the Institute of Microbial Chemistry in Tokyo. The enantioselective conversion of aldehyde 28 to α-fluoride 30 under catalysis by NHC 29 was developed (Angew. Chem. Int. Ed. 2012, 51, 10359) by Zhenyang Lin and Jianwei Sun at the Hong Kong University of Science and Technology.

Functional Group Reduction

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Catalytic Reduction ◽  
National Laboratory ◽  
Cobalt Complex ◽  
Selective Reduction ◽  
Aldehydes And Ketones ◽  
Effective System ◽  
Guanidinium Nitrate ◽  
Institute Of Technology ◽  
Indian Institute Of Science ◽  
The University

The reduction of azobenzene 1 with catalyst 2 was reported (J. Am. Chem. Soc. 2012, 134, 11330) by Alexander T. Radosevich at Pennsylvania State University, representing a unique example of a nontransition metal-based two-electron redox catalysis platform. Wolfgang Kroutil at the University of Graz found (Angew. Chem. Int. Ed. 2012, 51, 6713) that diketone 4 was converted to piperidinium 5 with very high stereoselectivity using a transaminase followed by reduction over Pd/C. Dennis P. Curran at the University of Pittsburgh reported (Org. Lett. 2012, 14, 4540) that NHC-borane 7 is a convenient reducing agent for aldehydes and ketones, showing selectivity for the former as in the monoreduction of 6 to 8. A catalytic reduction of esters to ethers with Fe3(CO)12 and TMDS, as in the conversion of 9 to 10, was developed (Chem. Commun. 2012, 48, 10742) by Matthias Beller at the Leibniz-Institute for Catalysis. Meanwhile, iridium catalysis was used (Angew. Chem. Int. Ed. 2012, 51, 9422) by Maurice Brookhart at the University of North Carolina at Chapel Hill for the reduction of esters to aldehydes with diethylsilane (e.g., 11 to 12). As an impressive example of selective reduction, Ohyun Kwon at UCLA reported (Org. Lett. 2012, 14, 4634) the conversion of ester 13 to aldehyde 14, leaving the malonate moiety intact. The cobalt complex 16 was found (Angew. Chem. Int. Ed. 2012, 51, 12102) by Susan K. Hanson at Los Alamos National Laboratory to be an effective catalyst for C=O, C=N, and C=C bond hydrogenation, including the conversion of alkene 15 to 17. The use of frustrated Lewis pair catalysis for the low-temperature hydrogenation of alkenes such as 18 was developed (Angew. Chem. Int. Ed. 2012, 51, 10164) by Stefan Grimme at the University of Bonn and Jan Paradies the Karlsruhe Institute of Technology. Guanidinium nitrate was found (Chem. Commun. 2012, 48, 6583) by Kandikere Ramaiah Prabhu at the Indian Institute of Science to catalyze the hydrazine-based reduction of alkenes such as 20. The hydrogenation of thiophenes is difficult for a number of reasons, but now Frank Glorius at the University of Münster has developed (J. Am. Chem. Soc. 2012, 134, 15241) an effective system for the highly enantioselective catalytic hydrogenation of thiophenes and benzothiophenes, including 22.

Functional Group Interconversion

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Carboxylic Acid ◽  
High Yield ◽  
Staudinger Ligation ◽  
University Of Alberta ◽  
University Of Tennessee ◽  
University Of British Columbia ◽  
National University ◽  
Seoul National University ◽  
Oxidative Amidation ◽  
The University

Glenn M. Samm is at the University of British Columbia reported (Angew. Chem. Int. Ed. 2012, 51, 10804) the photofluorodecarboxylation of aryloxyacids such as 1 using Selectfluor 2. Jean-François Paquin at the Université Laval found (Org. Lett. 2012, 14, 5428) that the halogenation of alcohols (e.g., 4 to 5) could be achieved with [Et2NSF2]BF4 (XtalFluor-E) in the presence of the appropriate tetraethylammonium halide. A method for the reductive bromination of carboxylic acid 6 to bromide 7 was developed (Org. Lett. 2012, 14, 4842) by Norio Sakai at the Tokyo University of Science. Professor Sakai also reported (Org. Lett. 2012, 14, 4366) a related method for the reductive coupling of acid 8 with octanethiol to produce thioether 9. The esterification of primary alcohols in water-containing solvent was achieved (Org. Lett. 2012, 14, 4910) by Michio Kurosu at the University of Tennessee Health Science Center using the reagent 11, such as in the conversion of alcohol 10 to produce 12 in high yield. Hosahudya N. Gopi discovered (Chem. Commun. 2012, 48, 7085) that the conversion of thioacid 13 to amide 14 was rapidly promoted by CuSO4. A ruthenium-catalyzed dehydrative amidation procedure using azides and alcohols, such as the reaction of 15 with phenylethanol to produce 16, was reported (Org. Lett. 2012, 14, 6028) by Soon Hyeok Hong at Seoul National University. An alternative oxidative amidation was developed (Tetrahedron Lett. 2012, 53, 6479) by Chengjian Zhu at Nanjing University and the Shanghai Institute of Organic Chemistry who utilized catalytic tetrabutylammonium iodide and disubstituted formamides to convert alcohols such as 17 to amides 18. A redox catalysis strategy was developed (Angew. Chem. Int. Ed. 2012, 51, 12036) by Brandon L. Ashfeld at Notre Dame for the triphenylphosphine-catalyzed Staudinger ligation of carboxylic acid 19 to furnish amide 20. For direct catalytic amidation of carboxylic acids and amines such as in the conversion of 21 to 23, Dennis G. Hall at the University of Alberta reported (J. Org. Chem. 2012, 77, 8386) that the boronic acid 22 was a highly effective catalyst that operated at room temperature.

Functional Group Transformations

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Gold Catalyst ◽  
Sulfonyl Chloride ◽  
Allylic Alcohol ◽  
West Virginia University ◽  
Israel Institute ◽  
University Of Texas ◽  
Amino Amide ◽  
Cu Catalyst ◽  
Institute Of Technology ◽  
The University

Mark Gandelman of the Technion–Israel Institute of Technology devised (Adv. Synth. Catal. 2011, 353, 1438) a protocol for the decarboxylative conversion of an acid 1 to the iodide 3. Doug E. Frantz of the University of Texas, San Antonio effected (Angew. Chem. Int. Ed. 2011, 50, 6128) conversion of a β-keto ester 4 to the diene 5 by way of the vinyl triflate. Pei Nian Liu of the East China University of Science and Technology and Chak Po Lau of the Hong Kong Polytechnic University (Adv. Synth. Catal. 2011, 353, 275) and Robert G. Bergman and Kenneth N. Raymond of the University of California, Berkeley (J. Am. Chem. Soc. 2011, 133, 11964) described new Ru catalysts for the isomerization of an allylic alcohol 6 to the ketone 7. Xiaodong Shi of West Virginia University optimized (Adv. Synth. Catal. 2011, 353, 2584) a gold catalyst for the rearrangement of a propargylic ester 8 to the enone 9. Xue-Yuan Liu of Lanzhou University used (Adv. Synth. Catal. 2011, 353, 3157) a Cu catalyst to add the chloramine 11 to the alkyne 10 to give 12. Kasi Pitchumani of Madurai Kamaraj University converted (Org. Lett. 2011, 13, 5728) the alkyne 13 into the α-amino amide 15 by reaction with the nitrone 14. Katsuhiko Tomooka of Kyushu University effected (J. Am. Chem. Soc. 2011, 133, 20712) hydrosilylation of the propargylic ether 16 to the alcohol 17. Matthew J. Cook of Queen’s University Belfast (Chem. Commun. 2011, 47, 11104) and Anna M. Costa and Jaume Vilarrasa of the Universitat de Barcelona (Org. Lett. 2011, 13, 4934) improved the conversion of an alkenyl silane 18 to the iodide 19. Vinay Girijavallabhan of Merck/Kenilworth developed (J. Org. Chem. 2011, 76, 6442) a Co catalyst for the Markovnikov addition of sulfide to an alkene 20. Hojat Veisi of Payame Noor University oxidized (Synlett 2011, 2315) the thiol 22 directly to the sulfonyl chloride 23. Nicholas M. Leonard of Abbott Laboratories prepared (J. Org. Chem. 2011, 76, 9169) the chromatography-stable O-Su ester 25 from the corresponding acid 24.

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