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. DOI: 10.1021/jacs.1c01472). 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. DOI: 10.1039/D1SC00528F). Jian Xu and Qi Wu of Zhejiang University reported an enzymatic system for the same transformation (Nature Commun. 2021, 12, 3983. DOI: 10.1038/s41467-021-24259-6).
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. DOI: 10.1016/j.tet.2021.132187). 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. DOI: 10.1039/D1CC00496D). 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. DOI: 10.1021/jacs.0c11209). 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. DOI: 10.1002/anie.202013561).
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. DOI: 10.1021/jacs.1c04427). 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. DOI: 10.1039/D1CC00047K).
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. DOI: 10.1002/chem.202005400). 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. DOI: 10.1021/jacs.1c04683). 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. DOI: 10.1021/jacs.1c01797). 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. DOI: 10.1021/acs.orglett.0c03748).
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. DOI: 10.1055/s-0040-1705959).