C-H Functionalization: The Shaw Synthesis of Panowamycin B
Qingtao Meng and Zhiqiang Zhang of the University of Science and Technology Liaoning and Yu-Peng He of the Dalian University of Technology used the amide of 1 to direct acetoxylation, leading to the ester 2 (J. Org. Chem. 2022, 87, 6378. DOI: 10.1021/acs.joc.2c00085). M. Christina White of the University of Illinois assembled the allylic amine 5 by coupling the alkene 3 with the amine 4 (Science 2022, 376, 276. DOI: 10.1126/science.abn8382). Soon Hyeok Hong of KAIST used mechanical grinding with the fluorosulfonamide 7 to convert the lactone 6 to the fluorinated product 8 (Adv. Synth. Cat. 2022, 364, 1975. DOI: 10.1002/adsc.202200206). Hans Renata of Scripps Florida used a mutated P450 to oxidize the diol 9 to the triol 10 (J. Am. Chem. Soc. 2022, 144, 7616. DOI: 10.1021/jacs.2c02958).
Timothy Noël of the University of Amsterdam used a decatungstate photocatalyst to couple 11 with the alkenyl phosphate 12, leading to the ester 13 (Chem. Sci. 2022, 13, 7325. DOI: 10.1039/D2SC01581A). Fei Pan of Sichuan Normal University assembled the alkyne 16 by coupling the amide 14 with the alkynyl sulfone 15 (Chem. Commun. 2022, 58, 2295. DOI: 10.1039/D1CC06885G). Xihe Bi of Northeast Normal University observed high regioselectivity in the formation of 19 by the the insertion of the carbene derived from 18 into 17 (Nature Commun. 2022, 13, 1674. DOI: 10.1038/s41467-022-29323-3). Paolo Melchiorre of ICIQ used a Binol-derived thiophosphoric acid to mediate the preparation of the ester 23 by the three-component coupling of the alkene 20, the pyridinium salt 21, and styrene 22 (J. Am. Chem. Soc. 2022, 144, 1113. DOI: 10.1021/jacs.1c11712).
Yoshihiro Matano of Niigata University cyclized the tosylhydrazone 24 to the pyrrolidine 25, via the intermediate diazo alkane (Org. Lett. 2022, 24, 3839. DOI: 10.1021/acs.orglett.2c01411). Jin-Quan Yu of Scripps La Jolla achieved high diastereoselectivity in the cyclization of the diacid 25 to the lactone 26 (Science 2022, 376, 1481. DOI: 10.1126/science.abq3048).
Gangguo Zhu of Zhejiang Normal University cyclized the alkyne 28 to the cyclopentene 29 (Angew. Chem. Int. Ed. 2022, 61, e202110864. DOI: 10.1002/anie.202110864). Alois Fürstner of the Max-Planck-Institut Mülheim generated an intermediate Ru carbene from the enyne 30, that cyclized to the cyclopentane 31 (J. Am. Chem. Soc. 2022, 144, 4158. DOI: 10.1021/jacs.1c13446).
In the course of a screening program for the treatment of tropical diseases, panowamycin B (34) was isolated from a culture of Streptomyces sp. K07-0010. Jared T. Shaw of the University of California, Davis constructed the isochroman skeleton of 34 by the Rh catalyzed diastereoselective cyclization to 33 of the diazo alkane derived from the hydrazone 32 (Angew. Chem. Int. Ed. 2022, 61, e202203072. DOI: 10.1002/anie.202203072).