Reduction: The Ogawa Synthesis of Maresin 2
Zheng Huang of the Shanghai Institute of Organic Chemistry showed that with an Ir catalyst, ethanol could serve as a reducing medium for the conversion of the alkyne 1 to the Z-alkene 2 (J. Am. Chem. Soc. 2021, 143, 4824. ). Jin Xie, Weipeng Li and Chengjian Zhu of Nanjing University devised conditions for the decarboxylative deuteration of the cesium carboxylate 3 to 4 (Chem. Sci. 2021, 12, 5505. ). Jian Xu and Qi Wu of Zhejiang University reported an enzymatic system for the same transformation (Nature Commun. 2021, 12, 3983. ).
Jean-Luc Renaud of Normandie Université established that an iron catalyst could effect the reduction of the unsaturated aldehyde 5 to the unsaturated alcohol 6 (Tetrahedron 2021, 90, 132187. ). Nathan D. Schley of Vanderbilt University used an Ir catalyst to effect the selective deoxygenation of the methyl glycoside 7 to the tetrahydropyran 8 (Chem. Commun. 2021, 57, 5953. ). Ming-Yu Ngai of the State University of New York, Stony Brook used a Pd catalyst to accomplish the selective 2-deoxygenation of the glucosyl bromide 9, leading to 10 (J. Am. Chem. Soc. 2021, 143, 1728. ). Andreas Gansäuer of the Universität Bonn used a titanocene catalyst to convert the epoxide 11 to the benzylidene acetal 12 (Angew. Chem. Int. Ed. 2021, 60, 5482. ).
Nathan T. Jui of Emory University found conditions for the reduction of the quaternary aryl ammonium salt 13 to the arene 14 (J. Am. Chem. Soc. 2021, 143, 8987. ). Xinxin Qi of Zhejian Sci-Tech University and Xiao-Feng Wu of the Dalian Institute of Chemical Physics reduced the nitroaromatic 15 in the presence of methyl carbonate, leading to the acetamide 16 (Chem. Commun. 2021, 57, 1955. ).
Jan Streuff of the Albert-Ludwigs-Universität Freiburg established that a titanocene catalyst was also effective for the desulfonylation of 17, leading to the nitrile 18 (Chem. Eur. J. 2021, 27, 6178. ). Jack R. Norton of Columbia University showed that with a Rh catalyst, the unsaturated aldehyde 19 could be hydrogenated to the saturated aldehyde 20 (J. Am. Chem. Soc. 2021, 143, 9657. ). Franziska Schoenebeck of RWTH Aachen used a Ni catalyst to mediate the migration of the distal alkene of the ketone 21, leading to the silyl enol ether 22 (J. Am. Chem. Soc. 2021, 143, 8375. ). Shaomin Fu and Bo Liu of Sichuan University observed that hydrogenation could open the activated cyclopropane of 23, to give 24 (Org. Lett. 2021, 23, 290. ).
Maresin 2 (26), isolated from human macrophages, showed strong antiinflammatory activity. Narihito Ogawa of Meiji University found that the reduction of the alkyne 25 to the Z-alkene, often difficult with such systems of extended conjugation, could be effected smoothly with activated zinc in methanol (Synlett 2021, 32, 295. ).