Monday, May 19, 2014
Douglass F. Taber
University of Delaware
Functional Group Oxidation and Reduction
Christophe Darcel and Jean-Baptiste Sortais of the CNRS-Université Rennes 1 reduced (Chem. Commun. 2013, 49, 10010. ) an acid 1 to the aldehyde 2 with a Mn catalyst under photostimulation. The same authors also used (Angew. Chem. Int. Ed. 2013, 52, 8045. ) an Fe catalyst to reduce an ester (not illustrated) to the corresponding aldehyde. Yasushi Tsuji of Kyoto University employed (Adv. Synth. Catal. 2013, 355, 3420. ) a Pd catalyst to reduce acid to the aldehydes. Chao-Jun Li of McGill University found (Angew. Chem. Int. Ed. 2013, 52, 11871. ) that a Ag catalyst in water would reduce an aldehyde 3 to the alcohol 4. Ketones were not reduced under these condtions.
David Milstein of the Weizmann Institute of Science devised (Angew. Chem. Int. Ed. 2013, 52, 14131. ) an Fe catalyst for the E-selective semireduction of an alkyne 5 to the alkene 6. Debabrata Maiti of IIT Bombay effected (Chem. Commun. 2013, 49, 8362. ) reductive cleavage of a nitrile 7 to the alkane 8. Aryl nitriles were also reduced.
Professor Li used (Eur. J. Org. Chem. 2013, 6496. ) an Ir catalyst and hydrazine under H-transfer conditions to reduce an alcohol 9 to the hydrocarbon 10. Kenneth M. Nicholas of the University of Oklahoma reduced (Chem. Commun. 2013, 49, 8199. ) the diol 11 to the alkene 12 with a V catalyst. Qiang Liu of Lanzhou University and Li-Zhu Wu of the Technical Institute of Physics and Chemistry showed (Eur. J. Org. Chem. 2013, 7528. ) that irradiation in the presence of a photoredox catalyst and a Hantzsch ester removed the sulfonyl group of 13.
Selective oxidation is a powerful tool for organic synthesis. Eike B. Bauer of the University of Missouri-St. Louis oxidized (Chem. Commun. 2013, 49, 5889. ) the diol 15 to the ketone 16 with an Fe catalyst and 30% hydrogen peroxide.
Yan-qin Yuan of Lishui University and Jian-nan Xiang of Hunan University selectively (Org. Lett. 2013, 15, 4654. ) thiolated the ether 17 to 18, that has the aldehyde oxidation state. Chengjian Zhu of Nanjing University converted (Adv. Synth. Catal. 2013, 355, 3558. ) the aldehyde 19 to the thioester 20 by oxidation in the presence of diphenyl disulfide. Shannon S. Stahl of the University of Wisconsin optimized (Org. Lett. 2013, 15, 5072. ) the oxidation of a primary alcohol 21 in the presence of methanol to the methyl ester 22. Nathaniel K. Szymczak of the University of Michigan observed (J. Am. Chem. Soc. 2013, 135, 16352. ) the remarkable oxidation of the amine 23 to the nitrile 24, with release of H2 gas.
Combining oxidation and reduction in the presence of a Ru catalyst, Soon Hyeok Hong of Seoul National University prepared (J. Am. Chem. Soc. 2013, 135, 11704. ) the amide 27 by combining the nitrile 25 with the alcohol 26. Francisco M. Guerra of the Universidad de Cádiz developed (Eur. J. Org. Chem. 2013, 8307. ) a Cu-Al oxide catalyst that proved effective for the γ-hydroxylation of an enone 28, delivering 29 with high diasteroselectivity.
D. F. Taber, Org. Chem. Highlights 2014, May 19.