Best Synthetic Methods: Oxidation and Reduction
Johannes G. de Vries of DSM Pharmaceuticals prepared (Chem. Commun. 2009, 3747. ) Fe nanoparticles that selectively mediated the hydrogenation of Z alkenes and not trisubstituted alkenes. This should allow the conversion of 1 to 2. In the course of a synthesis (Tetrahedron Lett. 2009, 50, 4368. ) of centrolobine, Teck-Peng Loh of Nanyang Technological University employed an elegant protocol for the reduction of the secondary bromide 3. István Markó of the Université catholique de Louvain observed (Tetrahedron 2009, 65, 10930. ) that toluates such as 5 can be reduced smoothly with SmI2 to the corresponding C-H.
Dan Yang of the University of Hong Kong devised (Org. Lett. 2009, 11, 3302. ) a triethylsilane-based procedure for the reductive amination of aldehydes and ketones such as 7. Jon A. Tunge of the University of Kansas developed (J. Am. Chem. Soc. 2009, 131, 16626. ) a complementary protocol for the conversion of an aldehyde or ketone to the protected amine 12. Mark T. Hamann of the University of Mississippi established (Tetrahedron Lett. 2009, 50, 3901. ) that a nitroaromatic 13 could be reduced in the presence of an acid chloride 14 to deliver the amide 15 directly. Matthias Beller of the Universität Rostock (Angew. Chem. Int. Ed. 2009, 48, 9507. ) and Hideo Nagashima of Kyushu University (Angew. Chem. Int. Ed. 2009, 48, 9511, ; J. Am. Chem. Soc. 2009, 131, 15032, ) reported parallel investigations of the silane-based reduction of an amide 16 to the amine 17.
Xue-Long Hou of the Shanghai Institute of Organic Chemistry demonstrated (Tetrahedron Lett. 2009, 50, 5578. ) that a terminal alkyne 18 could be oxidized to the α-acetoxy ketone 19. Philippe Renaud of the Universität Bern and Armido Studer of Westfälische-Wilhelms-Universität established (Angew. Chem. Int. Ed. 2009, 48, 6037. ) that both zinc enolates and silyl enol ethers could combine with chlorocatechol borane followed by TEMPO to give the α-oxygenated ketone. Stephen P. Marsden of the University of Leeds devised (Tetrahedron Lett. 2009, 50, 6106. ) a protocol for oxidizing a primary amine 18 to the benzoxazole 24, which has the oxidation state of the carboxylic acid. James M. Bobbitt and William F. Bailey of the University of Connecticut developed (J. Org. Chem. 2009, 74, 9524. ) the oxammonium salt 26 for the direct oxidation of benzyl ethers to ketones and carboxylic acids.
Rich G. Carter of Oregon State University effected (Org. Biomol. Chem. 2009, 7, 4582. ) oxidation of the complex sulfone 28 to the ketone 29. Kiumars Bahrami and Mohammad M. Khodaei of Razi University found (J. Org. Chem. 2009, 74, 9287. ) that oxidation of a thiol 30 to the sulfonyl chloride 31 could be followed by direct coupling to an amine to yield the sulfonamide.