Academic literature on the topic 'Phenanthroline-1,10(bis-(methyl-4 phenyl)-2,9)'

The sulfate ( + )-didemniserinolipid B 3, isolated from the tunicate Didemnum sp, has an intriguing spiroether core. A key step in the synthesis of 3 reported (Organic Lett. 2007, 9, 5357) by Steven D. Burke of the University of Wisconsin was the selective ring-closing metathesis of 1 to 2. The diol 6 that was used to prepare the ketal 1 was readily prepared from the inexpensive D-mannitol 4. Many other applications can be envisioned for the enantiomerically-pure diol 6 and for the monoacetate and bis acetate that are precursors to it. To set up the metathesis, the β, γ-unsaturated ketone 10 was needed. To this end, the keto phosphonate derived from the addition of the phosphonate anion 8 to the lactone 7 was condensed with phenyl acetaldehyde 9. The derived enone 10 was a 5:1 mixture of β, γ- and α, β-regioisomers. The diol 6 is C2 -symmetrical, but formation of the ketal 1 dissolved the symmetry, with one terminal vinyl group directed toward the styrene double bond, and the other directed away from it. On exposure to the first generation Grubbs catalyst, ring formation proceeded efficiently, to give 2. Williamson coupling with the serine-derived alcohol 11 then gave 12. To establish the secondary alcohol of 13 and so of 3, the more electron rich alkene of 12 was selectively epoxidized, from the more open face. Diaxial opening with hydride then gave 13. With 13 in hand, another challenge of selectivity emerged. The plan had been to attach the ester-bearing sidechain to 13 using alkene metathesis, then hydrogenate. As the side-chain of 3 contained an additional alkene, this had to be present in masked form. To this end, the α-phenylselenyl ester 14 was prepared. Alkene metathesis with 13 proceeded smoothly, this time using the second generation Grubbs catalyst. The unwanted alkene was then removed by reduction with diimide, and the selenide was oxidized to deliver the α, β-unsaturated ester.

John F. Hartwig of the University of California, Berkeley devised (Science 2014, 343, 853) conditions for the regioselective silylation of an arene 1 to give 2. The silyl group can directly be converted, inter alia, to halo, amino, alkyl, or hydroxyl. Jin-Quan Yu of Scripps La Jolla effected (Angew. Chem. Int. Ed. 2014, 53, 2683) regioselective alkenylation of the arene 3 with 4 to give 5. Wei-Liang Duan of the Shanghai Institute of Organic Chemistry described (Org. Lett. 2014, 16, 500) a related alkenyl­ation protocol. Deping Wang of Henyang Normal University developed (Eur. J. Org. Chem. 2014, 315) inexpensive conditions for the conversion of an aryl bromide 6 to the corre­sponding phenol 7. Mamoru Tobisu and Naoto Chatani of Osaka University used (J. Am. Chem. Soc. 2014, 136, 5587) a Ni catalyst to convert the lactam 8 to the aryl boro­nate 9. Patrick J. Walsh of the University of Pennsylvania found (Adv. Synth. Catal. 2014, 356, 165) conditions for the clean monoarylation of the amide 11 with 10 to give 12. In an application of the Catellani approach, Zhi- Yuan Chen of Jiangxi Normal University coupled (Chem. Eur. J. 2014, 20, 4237) the aryl iodide 13 with 14 to give the amino ester 15. Frederic Fabis of the Université de Caen-Basse-Normandie used (Chem. Eur. J. 2014, 20, 7507) Pd to catalyze the ortho halogenation (and alkoxylation) of the N-sulfonylamide 16 to give 17. Wen Wan of Shanghai University and Jian Hao of Shanghai University and the Shanghai Institute of Organic Chemistry effected (Chem. Commun. 2014, 50, 5733) ortho azidination of the aniline 18 with 19, leading to 20. Jianbo Wang of Peking University found (Angew. Chem. Int. Ed. 2014, 53, 1364) that the N-aryloxy amide 21 could be combined with the α-diazo ester 22 to give the ortho-alkenyl phenol 23. Silas P. Cook of Indiana University uncovered (Org. Lett. 2014, 16, 2026) remarkably simple conditions for the enantiospecific cyclization of 24 (65% ee) to 25 (63% ee). The development of arynes as reactive intermediates continues unabated. Xiaoming Zeng of Xi’an Jiaotong University developed (Org. Lett. 2014, 16, 314) the reagent 27 for the bis-functionalization of the aryne derived from 26.

Corey R. J. Stephenson of Boston University devised (Chem. Commun. 2011, 47, 5040) a protocol using visible light for removing the PMB group from 1 to give 2. John F. Hartwig, now at the University of California, Berkeley, developed (Science 2011, 332, 439) a Ni catalyst for the cleavage of the durable aryl ether of 3 to give 4. Mark S. Taylor of the University of Toronto devised (J. Am. Chem. Soc. 2011, 133, 3724) the catalyst 6, which selectively mediated esterifi cation of 5 to 7. Jean-Marie Beau of the Université Paris-Sud added (Chem. Commun. 2011, 47, 2146) Et3 SiH following the Fe-catalyzed deprotection-protection of 8, resulting in clean conversion to the bis ether 9. Mahmood Tajbakhsh of the University of Mazandaran showed (Tetrahedron Lett. 2011, 52, 1260) that guanidine HCl catalyzed the conversion of 10 to 11. Stephen W. Wright of Pfizer/Groton established (Tetrahedron Lett. 2011, 52, 3171) that the new urethane protecting group of 12, stable to many conditions, could be deprotected to 13 under conditions that spared even a Boc group. Matthias Beller of the Leibniz-Institute for Catalysis protected (Chem. Commun. 2011, 47, 2152) the amine 14 as the readily hydrolyzed imidazole 16. Sentaro Okamoto of Kanagawa University found (Org. Lett. 2011, 13, 2626) a simple reagent combination for the removal of the sometimes reluctant sulfonamide from 17. Jordi Burés and Jaume Vilarrasa of the Universitat de Barcelona removed (Angew. Chem. Int. Ed. 2011, 50, 3275) the oxime from 19 by Au-catalyzed exchange with 20. Pengfei Wang of the University of Alabama, Birmingham, designed (J. Org. Chem. 2011, 76, 2040) a range of photochemically removable protecting groups for aldehydes and ketones. Rafael Robles of the University of Granada selectively protected (J. Org. Chem. 2011, 76, 2277) the diol 24 using the reagent created by the activation of 25. Berit Olofsson of Stockholm University prepared (Org. Lett. 2011, 13, 3462) the phenyl ester 28 by exposing 27 to the diaryl iodonium triflate. Kannoth Manheri Muraleedharan of the Indian Institute of Technology, Madras, selectively (Org. Lett. 2011, 13, 1932) esterified 29 to 30 with catalytic SmCl3.