Monday, May 30, 2011
Douglass F. Taber
University of Delaware
Carbon-Carbon Bond Formation
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 Paris 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. The resulting phosphine oxide-containing polymer was easily separated from the product 27 by filtration. David M. Hodgson of the University of Oxford developed (Org. Lett. 2010, 12, 4204, not illustrated. ) an elegant Wittig-Schlosser approach to geometrically-defined trisubstituted alkenes.
Jianbo Wang of Peking University found (J. Am. Chem. Soc. 2010, 132, 13590. ) that an aryl tosylhydrazone 28, an aryl halide 29 and a terminal alkyne 30 could be coupled under Pd catalysis to give the branched product 31. This reaction is likely proceeding by formation of the Pd carbene complex from the intermediate aryl diazomethane.
Jacek Stawinski of Stockholm University observed (Org. Lett. 2010, 12, 4702. ) that the Pd-catalyzed coupling of an enantiomerically-enriched propargylic carbonate 32 with 33 gave the allenyl phosphonate 34 with high stereocontrol. They used this same protocol to prepare allenyl phosphonates that were chiral at phosphorus.
D. F. Taber, Org. Chem. Highlights 2011, May 30.