Organic Chemistry Portal
Organic Chemistry Highlights

Monday, May 18, 2015
Douglass F. Taber
University of Delaware

New Methods for Reduction and for Oxidation

Clemens Krempner of Texas Tech University devised (Chem. Eur. J. 2014, 20, 14959. DOI: 10.1002/chem.201404994) a very active Al catalyst for the Meerwein-Ponndorf-Verley reduction of a ketone 1 to the alcohol 2. Louis Fensterbank and Cyril Ollivier of UMPC and Jean-Philippe Goddard of the Université de Haute-Alsace showed (Adv. Synth. Catal. 2014, 356, 2756. DOI: 10.1002/adsc.201400729) that visible light could mediate the reduction of the O-thiocarbamate 3 to 4. Soon Hyeok Hong of Seoul National University used (Org. Lett. 2014, 16, 4404. DOI: 10.1021/ol501835t) hydrogen from the diol 6 to reduce the nitrile 5, leading directly to the protected amine 7.

Alex Adronov of McMaster University (J. Org. Chem. 2014, 79, 7728. DOI: 10.1021/jo501299j) and Thibault Cantat of Gif-sur-Yvette (Chem. Commun. 2014, 50, 9349. DOI: 10.1039/C4CC02894E) observed that an aryl amide 8 could be reduced to the amine 9 under conditions that left alkyl amides unchanged. Paul J. Chirik of Princeton University developed (J. Am. Chem. Soc. 2014, 136, 13178. DOI: 10.1021/ja507902z) a Co catalyst for the alcohol-directed reduction of a proximal alkene, converting 10 selectively to 11. Yoichiro Kuninobu and Motomu Kanai of the University of Tokyo used (Synlett 2014, 25, 1869. DOI: 10.1055/s-0034-1378315) stoichiometric Mo(CO)6 to desulfurize 12 to 13.

Utpal Bora of Tezpur University oxidized (Tetrahedron Lett. 2014, 55, 5029. DOI: 10.1016/j.tetlet.2014.07.047) the alcohol 14 to the aldehyde 15 with t-butyl hydroperoxide, using the inexpensive and reusable VOSO4 as the catalyst. The oxidation of an alcohol to the acid is often carried out in two steps, alcohol to aldehyde and aldehyde to carboxylic acid. Kenneth B. Wagener of the University of Florida developed (Tetrahedron Lett. 2014, 55, 4452. DOI: 10.1016/j.tetlet.2014.06.055) a protocol for the direct oxidation of an alcohol 16 to the acid 17. Prodeep Phukan of Gauhati University devised (Tetrahedron Lett. 2014, 55, 5358. DOI: 10.1016/j.tetlet.2014.07.124) a catalyst-free procedure for the oxidation of a primary alcohol 18 to the ester 19. The aldehyde corresponding to 18 (not illustrated) was also efficiently oxidized to 19.

Katsuhiko Moriyama and Hideo Togo of Chiba University effected (Org. Lett. 2014, 16, 3812. DOI: 10.1021/ol501703y) the oxidative debenzylation of 20 to the ketone 21. Christian Ochsenfeld and Dirk Trauner of the University of Munich used (J. Org. Chem. 2014, 79, 9812. DOI: 10.1021/jo501206k) Swern conditions to selectively oxidize the TES ether 22 to the aldehyde 23. Satoshi Minakata of Osaka University devised (Org. Lett. 2014, 16, 4646. DOI: 10.1021/ol5022433) conditions for the oxidative decarboxylation of a β,γ-unsaturated acid 24 to the allylic acetate 25. Justin J. Maresh of DePaul University prepared (Tetrahedron Lett. 2014, 55, 5047. DOI: 10.1002/ejoc.201403112) the aldehyde 27 by oxidative decarboxylation of the amino acid 26. Dirk E. De Vos of KU Leuven used (Eur. J. Org. Chem. 2014, 6649. DOI: 10.1002/ejoc.201403112) electrochemically-generated hypobromite for the oxidative decarboxylation of an amino acid to the corresponding nitrile (not illustrated). Yujiro Hayashi of Tohoku University established (Chem. Eur. J. 2014, 20, 15753. DOI: 10.1002/chem.201403475) conditions for the Nef oxidation of a nitro alkene 28 to the enone 29.

D. F. Taber, Org. Chem. Highlights 2015, May 18.