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Monday, May 23, 2022
Douglass F. Taber
University of Delaware

Reactions of Alkenes: The Yang Synthesis of Bisdihydrotuberostemonine D

Qiang Liu and Yibiao Li of Wuyi University developed a simple protocol for exchanging deuterium into the alkene 1, leading to 2 (Org. Lett. 2021, 23, 7412. ). Joseph M. Ready of the UT Southwestern Medical Center found that under visible irradiation, the activated ester 4 could be added to the alkene 3, leading to the anti-Markovnikov ester 5 (ACS Catal. 2021, 11, 13714. ). In a parallel investigation, Bing Han of Lanzhou University assembled the anti-Markovnikov carbonate 8 by photochemically-promoted combination of the alkene 6 with the oxime carbonate 7 (Angew. Chem. Int. Ed. 2021, 60, 21997. ). Zachary K. Wickens of the University of Wisconsin showed that via electrolyic oxidation of thianthracene 9, the alkene 6 could be converted to the Z-allylic amine 10 (J. Am. Chem. Soc. 2021, 143, 21503. ).

Ignacio Funes-Ardoiz of the Universidad de La Rioja and Juntao Ye of Shanghai Jiao Tong University prepared the alkylated malonate 12 by the photochemically-promoted addition of diethyl malonate 11 to the alkene 6 (J. Am. Chem. Soc. 2021, 143, 11251. ). Yasuhiro Yamashita and Shū Kobayashi of the University of Tokyo also used visible light to effect the coupling of the silyl enol ether 13 with the alkene 14, leading to the alkylated cyclohexanone 15 (Org. Lett. 2021, 23, 5693. ). Yusuke Ano of Osaka University used a Pd catalyst to mediate the 1,1-addition of the bromoalkyne 17 to the alkene 16, to give 18 (Chem. Sci. 2021, 12, 12326. ). Chao Yang and Wujiong Xia of the Harbin Institute of Technology developed the photochemically-promoted addition of ethyl diazoacetate 20 and a diaryl amine to the alkene 19, leading to the γ-aminoester 21 (Org. Lett. 2021, 23, 6278. ).

Under the photochemical conditions devised by Chuan-Ming Jin of Hubei Normal University and Ji-Chang Xiao of the Shanghai Institute of Organic Chemistry, cyanide was generated in situ, allowing the assembly of the cyanoester 23 by the addition of the bromoacetate 22 to the alkene 6 (Chem. Commun. 2021, 57, 2649. ). Xiao-Feng Wu of the Dalian Institute of Chemical Physics established the directed Pd-catalyzed carbonylation of the alkene 24, leading to the β-boryl ketone 25 (Chem. Sci. 2021, 12, 10341. ). Ramesh Giri of Pennsylvania State University assembled the ketone 29 by Ni-catalyzed addition of the enol triflate 28 and the aryl borate 27 to the alkene 26 (Angew. Chem. Int. Ed. 2021, 60, 19092. ). Alain de Mesmaeker of Syngenta showed that the intermediate enamine from the addition of the dialkyl amide 30 to the alkene 6 could be coupled with ethyl acrylate 31, to give the cyclobutanone 32 (Helv. Chim. Acta 2021, 104, e2100022. ).

The alkaloid bisdihydrotuberostemonine D (35) was isolated from the roots of the Chinese vine Stemona tuberosa. En route to 35, Yu-Rong Yang of the Kunming Institute of Botany demonstrated that the exo methylene of 33 could be isomerized to the more stable endocyclic alkene 34 in the presence of the internal alkene (J. Am. Chem. Soc. 2021, 143, 20622. ).

D. F. Taber, Org. Chem. Highlights 2022, May 23.