Academic literature on the topic 'Furan opening'

Dihomo-Isofurans, produced in vivo by oxidation of adrenic acid, are potential mark­ers of neuronal oxidative damage. Jetty Chung-Yung Lee of the University of Hong Kong and Jean-Marie Galano of Université de Montpellier I and II described (Angew. Chem. Int. Ed. 2014, 53, 6249) the cyclization of 1 to 2, opening what should be a gen­eral route to these furans.

James A. Bull of Imperial College London showed (Angew. Chem. Int. Ed. 2014, 53, 14230) that the malonate 1 could readily be cyclized to the oxetane 2. Davide Ravelli of the University of Pavia functionalized (Adv. Synth. Catal. 2014, 356, 2781) the α position of the oxetane 3 with 4, leading to 5. Frank Glorius of the Westfälische Wilhelms-Universität Münster hydrogenated (Angew. Chem. Int. Ed. 2014, 53, 8751) the furan 6 to give 7 in high ee. Jia-Rong Chen and Wen-Jing Xiao of Central China Normal University converted (Eur. J. Org. Chem. 2014, 4714) the initial Henry adduct from 8 into the cyclic ether 9. Anil K. Saikia of the Indian Institute of Technology, Guwahati cyclized (J. Org. Chem. 2014, 79, 8592) the ene–yne 10 to the ketone 11. Richard C. D. Brown of the University of Southampton developed (Org. Lett. 2014, 16, 5104) a chiral auxiliary that effectively directed the oxidative cyclization of the diene 12 to 13. The chiral auxiliary could be recovered and reused. K. A. Woerpel of New York University showed (Org. Lett. 2014, 16, 3684) that, depending on the solvent, 15 could be added to 14 to give either 16 or 17. Samuel J. Danishefsky of Columbia University and the Memorial Sloan-Kettering Cancer Center also observed (Chem. Eur. J. 2014, 20, 8731) a marked solvent effect on the diastereoselectivity of the reduction of 18 to 19. Xiaoming Feng of Sichuan University added (Chem. Eur. J. 2014, 20, 14493) the ketone 20 to Danishefsky’s diene 21 to give 22 in high ee. Jhillu Singh Yadav of the Indian Institute of Chemical Technology effected (Tetrahedron Lett. 2014, 55, 3996) intramolecular opening of the oxetane of 23 to give, with clean inversion, the cyclic ether 24. Chun-Yu Ho of the South University of Science and Technology, taking advan­tage (J. Org. Chem. 2014, 79, 11873) of the superior chelating ability of the allyl ether, selectively cyclized 25 to 26. Xuegong She of Lanzhou University used (Angew. Chem. Int. Ed. 2014, 53, 10789) a gold catalyst to convert 27 into the eight-membered ring ether 28.

Mei-Huey Lin of the National Changhua University of Education rearranged (J. Org. Chem. 2014, 79, 2751) the initial allene derived from 1 to the γ-chloroenone. Displacement with acetate followed by hydrolysis led to the furan 2. A. Stephen K. Hashmi of Ruprecht-Karls-Universität Heidelberg showed (Angew. Chem. Int. Ed. 2014, 53, 3715) that the Au-catalyzed conversion of the bis alkyne 3, mediated by 4, proceeded selectively to give 5. Tehshik P. Yoon of the University of Wisconsin used (Angew. Chem. Int. Ed. 2014, 53, 793) visible light with a Ru catalyst to rearrange the azide 6 to the pyrrole 7. Cheol-Min Park, now at UNIST, found (Chem. Sci. 2014, 5, 2347) that a Ni catalyst reorganized the methoxime 8 to the pyrrole 9. A Rh catalyst converted 8 to the corresponding pyridine (not illustrated). In the course of a synthesis of opioid ligands, Kenner C. Rice of the National Institute on Drug Abuse optimized (J. Org. Chem. 2014, 79, 5007) the preparation of the pyridine 11 from the alcohol 10. Vincent Tognetti and Cyrille Sabot of the University of Rouen heated (J. Org. Chem. 2014, 79, 1303) 12 and 13 under micro­wave irradiation to give the 3-hydroxy pyridine 14. Tomislav Rovis of Colorado State University prepared (J. Am. Chem. Soc. 2014, 136, 2735) the pyridine 17 by the Rh-catalyzed combination of 15 with 16. Fabien Gagosz of the Ecole Polytechnique rearranged (Angew. Chem. Int. Ed. 2014, 53, 4959) the azirine 18, readily available from the oxime of the β-keto ester, to the pyridine 19. Matthias Beller of the Universität Rostock used (Chem. Eur. J. 2014, 20, 1818) a Zn catalyst to mediate the opening of the epoxide 21 with the aniline 20. A Rh cata­lyst effected the oxidation and cyclization of the product amino alcohol to the indole 22. Sreenivas Katukojvala of the Indian Institute of Science Education & Research showed (Angew. Chem. Int. Ed. 2014, 53, 4076) that the diazo ketone 23 could be used to anneal a benzene ring onto the pyrrole 24, leading to the 2,7-disubstituted indole 25.

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.

The cost of using Grubbs-type catalysts could be reduced dramatically if the turnover could be improved. Richard L. Pederson of Materia found (Organic Lett. 2010, 12, 984) that in MTBE at 50°C, the ring-closing metathesis of 1 proceeded to completion in 8 hours with just 500 ppm of H2 catalyst 2. Jianhui Wang of Tianjin University constructed (Angew. Chem. Int. Ed. 2010, 49, 4425) a modified H2 catalyst 5 tethered to a nitrobenzospiropyran. After the cyclization of 4 to 6 was run in CH2Cl2, the mixture was irradiated with visible light, converting 5 into its ionic form, which could be extracted with glycol/methanol, leaving little Ru residue in the cyclized product. In the dark, the catalyst reverted and could be extracted back into CH2Cl2 and reused. In a complementary approach, David W. Knight of Cardiff University found (Tetrahedron Lett. 2010, 51, 638) that the residual Ru after metathesis could be reduced to < 2 ppm simply by stirring the product with H2O2. Cyclopropenes such as 6 are readily available in enantiomerically pure form by the addition of diazoacetates to alkynes. Christophe Meyer and Janine Cossy of ESPCI ParisTech showed (Organic Lett. 2010, 12, 248) that with a Ti additive, G2 cyclized 7 to 8. Siegfried Blechert of the Technische Universität Berlin devised (Angew. Chem. Int. Ed. 2010, 49, 3972) the chiral Ru catalyst 11, which converted the prochiral 9 to 12 in high ee. Daesung Lee of the University of Illinois, Chicago, explored (J. Am. Chem. Soc. 2010, 132, 8840) the cyclization of the diyne 13 with 14 under G2 catalysis. Depending on the terminal substituent, the cyclization could be directed selectively to 15 or 16. Bran C. Goess of Furman University took advantage (J. Org. Chem. 2010, 75, 226) of alkyne ring-closing metathesis for the conversion of 17 to 18. Selective hydrogenation then delivered the boll weevil pheromone grandisol 19. Cyrille Kouklovsky and Guillaume Vincent of the Université de Paris Sud extended (J. Org. Chem. 2010, 75, 4333) ring-opening/ring-closing metathesis to the nitroso Diels-Alder adduct 20. Reduction led to 8-epihalosilane 22.