Substituted Benzenes: The Fujiwara Synthesis of Selaginellin A
Zhuangzhi Shi of Nanjing University devised a protocol for converting an arene 1 to the corresponding phenol 2 (Nature Commun. 2020, 11, 1316. DOI: 10.1038/s41467-020-15207-x). Damoder Reddy Motati and E. Blake Watkins of Union University observed high regioselectivity in the bromination of 3, leading to 4 (Org. Chem. Front. 2020, 7, 1095. DOI: 10.1039/C9QO01508F). Yuanhua Wang of Sichuan University used a Rh catalyst to mediate the conversion of 5 to 6 (Chem. Eur. J. 2020, 26, 6805. DOI: 10.1002/chem.201905855). John R. Falck of the University of Texas Southwestern Medical Center achieved direct meta amination of 7, to give 8 (J. Am. Chem. Soc. 2020, 142, 5266. DOI: 10.1021/jacs.9b13753).
Jennifer L. Roizen of Duke University coupled a sulfamate ester with 9 to give 10 (Org. Lett. 2019, 21, 7049. DOI: 10.1021/acs.orglett.9b02621). Mark Stradiotto of Dalhousie University described a parallel investigation with sulfonamides (Angew. Chem. Int. Ed. 2020, 59, 8952. DOI: 10.1002/anie.202002392). The conversion of 11 to 12 reported by Takashi Ikawa and Shuji Akai of Osaka University proceeded via a benzyne intermediate (Chem. Eur. J. 2020, 26, 4320. DOI: 10.1002/chem.201904987).
Alex M. Szpilman of Ariel University assembled the ketone 15 by coupling 14 with the alkenyl azide 13 (Org. Lett. 2020, 22, 768. DOI: 10.1021/acs.orglett.9b03824). Liam T. Ball of the University of Nottingham converted 16 in situ to an aryl bismuth intermediate that, after oxidation with mCPBA, arylated phenol 17 to give 18 (Nature Chem. 2020, 12, 260. DOI: 10.1038/s41557-020-0425-4). Ashot Gevorgyan and Annette Bayer of UiT the Arctic University of Norway effected carboxylation of 19, leading to 20 (Chem. Eur. J. 2020, 26, 6064. DOI: 10.1002/chem.202000515). Liguang Luo and Weibo Yang of the Shanghai Institute of Materia Medica prepared 23 by alkylating the acid 21 with 22 (Nature Commun. 2020, 11, 2151. DOI: 10.1038/s41467-020-16084-0). Benzoic acids such as 20 and 21 are versatile intermediates. Sharon R. Neufeldt of Montana State University and Joseph J. Topczewski of the University of Minnesota prepared biaryls by coupling the silver salts of benzoic acids with aryl halides (J. Am. Chem. Soc. 2020, 142, 13210. DOI: 10.1021/jacs.0c06244). Stephen G. Newman of the University of Ottawa reduced benzoic acid methyl esters to methyl groups (J. Am. Chem. Soc. 2020, 142, 8109. DOI: 10.1021/jacs.0c02405), and Naoto Chatani, also of Osaka University, effected reductive decarboxylation of benzoic acid esters (Chem. Commun. 2019, 55, 13610. DOI: 10.1039/C9CC07710C).
Huiying Zeng of Lanzhou University and Chao-Jun Li of McGill University assembled the phenol 26 by oxidizing a mixture of 24 and 25 (Chem. Commun. 2020, 56, 1239. DOI: 10.1039/C9CC09347H). Fang Liu of Nanjing Agricultural University and Karl Anker Jørgensen of Aarhus University prepared the benzylic silane 29 in high ee by the Hayashi organocatalyst mediated addition of 28 to 27 followed by irradiation (J. Am. Chem. Soc. 2020, 142, 6030. DOI: 10.1021/jacs.9b11579).
Selaginellin D (33), isolated from the spikemoss Selaginella pulvinata, showed interesting bioactivity. Kenshu Fujiwara of Akita University assembled the aromatic core 32 of 33 by the Diels-Alder addition of 30 to 31 followed by oxidation (Tetrahedron Lett. 2020, 61, 152031. DOI: 10.1016/j.tetlet.2020.152031).