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Monday, November 25, 2019
Douglass F. Taber
University of Delaware

Carbon-Carbon Bond Formation: The Li Synthesis of Longirabdiol

Hirohisa Ohmiya of Kanazawa University assembled 3 by coupling 1 with 2 (Chem. Eur. J. 2019, 25, 724. ). Using 4 as a linchpin, Takahiro Nishimura of Osaka City University sequentially added two unlike alkenes, 5 and 6, leading to the amine 7 (Adv. Synth. Catal. 2018, 360, 4827. ). Mary P. Watson of the University of Delaware activated the amine 8 with 9, then coupled the product with 10 to give 11 (J. Am. Chem. Soc. 2019, 141, 2257. ). Varinder K. Aggarwal of the University of Bristol used the same strategy to effect conjugate addition (Angew. Chem. Int. Ed. 2019, 58, 5697. ). Chen Zhu of Soochow University used visible light activation to prepare the 1,8-diketone 14 by combining 12 with 13 (Chem. Commun. 2019, 55, 2368. ).

Yasushi Nishihara of Okayama University converted the acid chloride 15 into 16 (Org. Lett. 2019, 21, 3640. ). Gwilherm Evano of the Université libre de Bruxelles iodinated the intermediate from adding 18 to 17, leading to 19 (Org. Lett. 2019, 21, 4318. ). Biplab Maji of the Indian Institute of Science Education and Research Kolkata also used visible light, to promote the addition of 20 to 21 to give 22 (Org. Lett. 2019, 21, 3755. ). Nuno Maulide of the University of Vienna prepared the diene 25 by opening the lactone 24 with 23 (Synlett 2019, 30, 413. ).

Manuel van Gemmeren of the Westfälische Wilhelms-Universität Münster effected net triple dehydration of the α-hydroxy ketone 26 to the alkyne 27 (J. Org. Chem. 2019, 84, 983. ). Morteza Shiri of Alzahra University developed the Pd-catalyzed conversion of 28 to the amide 29 (Adv. Synth. Catal. 2019, 361, 118. ).

Shenming Ma of Zhejiang University coupled 31 with racemic 30 to give the disubstituted allene 32 in high ee (Nature Commun. 2019, 10, 507. ). Pengfei Li of Southern University of Science and Technology and Wenjun Li of Qingdao University prepared the tetrasubstituted allene 35 by combining 33 with 34 (Org. Lett. 2019, 21, 503. ).

Longirabdiol (39), also known as macrocalyxoformin D, is an ent-kaurane isolated from the trumpet spurflower Rabdosia longituba. In the course of a synthesis of 39, Chao Li of the National Institute of Biological Sciences assembled the substituted cyclohexane starting material 38 via the decarboxylative coupling of 36 with 37 (J. Am. Chem. Soc. 2019, 141, 8372. ).

D. F. Taber, Org. Chem. Highlights 2019, November 25.
URL: https://www.organic-chemistry.org/Highlights/2019/25November.shtm