Organic Chemistry Portal
Organic Chemistry Highlights

Monday, January 22, 2024
Douglass F. Taber
University of Delaware

Reduction: The Tadpetch Synthesis of Pestalotioprolide B

Xiongjie Jin and Kyoko Nozaki of the University of Tokyo established an effective protocol for the hydrogenation of an ester 1 to the corresponding hydrocarbon 2 (J. Am. Chem. Soc. 2023, 145, 3454. DOI: 10.1021/jacs.2c11145). Charles S. Yeung of Merck and Zachary K. Wickens of the University of Wisconsin devised the single electron transfer reduction of a benzoate 3 to the hydrocarbon 4 (Angew. Chem. Int. Ed. 2023, 62, e202300178. DOI: 10.1002/anie.202300178). Yang Li of Xi'an Jiaotong University also used visible light to promote the decarboxylation of the α-keto carboxylic acid 5 to the C1-deuterated aldehyde 6 (J. Org. Chem. 2023, 88, 6401. DOI: 10.1021/acs.joc.2c02299). Richmond Sarpong of the University of California, Berkeley used related conditions to fragment the secondary alcohol 7 to the corresponding aldehyde, that was directly reduced to the alcohol 8 (Chem. Commun. 2023, 59, 3858. DOI: 10.1039/D3CC00945A).

Ekambaram Balaraman of the Indian Institute of Science Education and Research, Kishore Natte of the Indian Institute of Technology Hyderabad and Rajenahally V. Jagadeesh of the Leibniz-Institut für Katalyse e.V. used methanol to hydrogenate the aldehyde 9 to the alcohol 10 (J. Org. Chem. 2023, 88, 2245. DOI: 10.1021/acs.joc.2c02657). Hong-Yan Shang and Yuan-Yu Tian of the China University of Petroleum reduced the epoxide 11 to the primary alcohol 12 (Eur. J. Org. Chem. 2023, 26, e202300111. DOI: 10.1002/ejoc.202300111). Xiaomin Xie and Zhaoguo Zhang of Shanghai Jiao Tong University showed that 1,1,3,3-tetramethyldisiloxane 14 was effective for reducing the amide 13 to the hemiaminal, that was hydrolyzed to the aldehyde 15 (Org. Chem. Front. 2023, 10, 1198. DOI: 10.1039/D2QO01766K). Xiaotian Qi of the University of the Chinese Academy of Sciences and Chao Liu of the Lanzhou Institute of Chemical Physics used the 4-aminopyridine 17 in conjunction with triflic anhydride to reduce the carboxylic acid 16 to the aldehyde 18 (Angew. Chem. Int. Ed. 2023, 62, e202215168. DOI: 10.1002/anie.202215168).

Vinothkumar Vinayagam of Curia India Pvt. Ltd developed a photochemical protocol for reducing the amide of 19 to the amine 20, without reducing the ester (J. Org. Chem. 2023, 88, 2122. DOI: 10.1021/acs.joc.2c02543). In another contribution from the Leibniz-Institut für Katalyse e.V., Rajenahally V. Jagadeesh and Matthias Beller in collaboration with Denis Chusov of the A. N. Nesmeyanov Institute of Organoelement Compounds used CO-rich convertor gas to effect the reductive amination of the aldehyde 21 with the amine 22, leading to the amine 23 (Chem. Sci. 2023, 14, 4346. DOI: 10.1039/D3SC00257H). Yan-Qiang Zhang, also of the University of the Chinese Academy of Sciences and Bao-Hua Xu of the Beijing Institute of Technology prepared the amine 26 by the reductive amination of the ketone 24 with the nitrile 25 (Org. Biomol. Chem. 2023, 21, 1450. DOI: 10.1039/D2OB02312A). Yunhui Yang and Congyang Wang of the Institute of Chemistry of the Chinese Academy of Sciences hydrogenated the thioamide 27 to the amine 28 (Angew. Chem. Int. Ed. 2023, 62, e202215963. DOI: 10.1002/anie.202215963).

Pestalotioprolide B (31) was isolated from the mangrove-derived polyurethane-digesting fungus Pestalotiopsis microspora. En route to 31, Kwanruthai Tadpetch of the Prince of Songkla University effected the selective reduction of the propargylic alcohol 29 to the (E)-allylic alcohol 30 (Eur. J. Org. Chem. 2023, 26, e202300034. DOI: 10.1002/ejoc.202300034).

D. F. Taber, Org. Chem. Highlights 2024, January 22.