Swadeshmukul Santra of the University of Central Florida described(Tetrahedron Lett. PMID:36628218 2009, 50, 124.DOI: 10.1016/j.tetlet.2008.10.110)a simple preparation of silica nanoparticles that efficiently catalyzed theanti-Markovnikov addition of thiophenol to alkenes (illustrated), and also toalkynes. Akiya Ogawa of Osaka Prefecture University devised(Tetrahedron Lett. 2009, 50, 624.DOI: 10.1016/j.tetlet.2008.11.079)a protocol for the photoinduced hydrophosphinylation of an alkene 3 to thephosphine oxide 4. Xavi Ribas and Miquel Costas of the University of Girona developed(Adv. Synth. Catal. BuyPyrazine-2,3-diamine 1367777-12-5 manufacturer 2009, 351, 348.DOI: 10.1002/adsc.200800650)a manganese catalyst for the epoxidation of alkenes with 30%H2O2. Masahito Ochiai of the University of Tokushima established(J. Am. Chem. Soc. 2009, 131, 1382.DOI: 10.1021/ja808829t)an iodoarene-catalyzed oxidation of an alkene 7 to the keto acid 9.If, as is likely, isolated alcohols are stable under these conditions, thiswill be a useful complement to RuO4 cleavage.
Several methods are available for homologating unactivated alkenes.Sven Doye of the Universität Oldenburg observed(Angew. Chem. Int. Ed. 2009, 48, 1153.DOI: 10.1002/anie.200805169)that a Ti catalyst could effect the addition of N-methyl aniline 10to the alkene 3, to give the branched product 11. The reactionalso worked well in an intramolecular sense. Note that in this process, a C-Hbond is also converted to a C-C bond. Kiyoshi Tomioka of Kyoto University reported(Org. Lett. 2009, 11, 2007.DOI: 10.1021/ol900447n)that the Suzuki coupling of the hydroboration product from 12 with theiodo alkene 13 was best supported by AsPh3.
Teck-Peng Loh of Nanyang Technological University showed(J. Am. Chem. Soc. 2009, 131, 1372.DOI: 10.1021/ja8084548)that the homologation of an isolated alkene 15 with an acrylate ester 16could also be carried out under oxidative conditions, to give the diene 17.Weiping Su of the Fujian Institute of Research on the Structure of Matter found(Org. Lett. 2009, 11, 2341.DOI: 10.1021/ol9007553)that similar oxidative conditions effected the decarboxylative addition of an aromatic acid such as 18 to an alkene to give the substituted styrene19.
Kian L. Tan of Boston College took advantage(Org. Lett. 2009, 11, 2764.DOI: 10.1021/ol900921e)of a chelating ligand to direct the regioselective hydroformylation of anallylic sulfonamide 20. Isolated internal alkenes were stable underthese conditions. Barry M. Trost of Stanford University described(Org. Lett. 2009, 11, 1071.DOI: 10.1021/ol8028324)the Ru-catalyzed cross coupling of an alkynyl ester 23 with a protected allylic alcohol22 to give the 1,3-diene 24. The process is highly Z-selective, as would be expected for alkene formation by β-hydride elimination.
Sylvain Darses of the Ecole National Supériore de Chimie de Paris devised(Adv. Synth. Catal. 2009, 351, 153.DOI: 10.1002/adsc.200800600)a Ru catalyst for the addition of an alkenyl silane such as 26 to an alkene 25 bearing an electron-withdrawing group, leadingto the homologated product 27. Kazuhiko Takai of Okayama University uncovered(Org. Lett. 2009, 11, 2711.DOI: 10.1021/ol900962v)a conceptually related process for the directed homologation of the alkenyl Hof 28 to give 29. The imidazole of 30 is interesting in its own rightand could also be hydrolyzed to the corresponding carboxylic acid.
