Organic Chemistry Portal
Organic Chemistry Highlights

Monday, January 8, 2024
Douglass F. Taber
University of Delaware

C-O Ring Construction: The Menche Synthesis of Pentamycin

Guisheng Zhang and Zhiguo Zhang of Henan Normal University rearranged the activated cyclopropane 1 with catalytic 2, leading to the dihydrofuran 3 (J. Org. Chem. 2023, 88, 1003. DOI: 10.1021/acs.joc.2c02415). Trevor A. Hamlin of the Vrije Universiteit Amsterdam and Darren J. Dixon of the University of Oxford achieved high enantioselectivity in the bifunctional iminophosphorane-catalyzed cyclization of the unsaturated amide 4 to the tetrahydrofuran 5 (J. Am. Chem. Soc. 2023, 145, 12771. DOI: 10.1021/jacs.3c03182). Minyang Wang of Nanjing University and Wangqing Kong of Wuhan University showed that depending on the choice of catalyst and protecting group, the coupling of tetrahydrofuran 6 with the aryl bromide 7 could be directed to either the 2,3-product 8, or the regioisomeric 2,4-product (J. Am. Chem. Soc. 2023, 145, 5231. DOI: 10.1021/jacs.2c12481). In support of a synthesis of eribulin, Feng Lin of WuXi AppTech and Wei Li of China Pharmaceutical University showed that coupling of the tetrahydrofuran 9 with the allyl silane 10 led to 11 with high diastereoselectivity (Org. Process Res. Dev. 2023, 27, 367. DOI: 10.1021/acs.oprd.2c00370). Robert Britton of Simon Fraser University reported a complementary approach to eribulin (Nature Commun. 2023, 14, 1904. DOI: 10.1038/s41467-023-37346-7).

Dzmitry G. Kananovich of the the Tallinn University of Technology and Iryna V. Mineyeva of the Belarusian State University showed that depending on conditions, cyclization of the unsaturated ester 12 could be directed toward either diastereomer of the tetrahydropyran 13 (J. Org. Chem. 2023, 88, 355. DOI: 10.1021/acs.joc.2c02382).

Nobuya Tsuji and Pavel Sidorov of Hokkaido University, Alexandre Varnek of the University of Strasbourg and Benjamin List of the Max-Planck-Institut für Kohlenforschung used a machine learning model to optimize an imidophosphorimidate catalyst for the enantioselective cyclization of the unsaturated alcohol 14 to the tetrahydropyran 15 (Angew. Chem. Int. Ed. 2023, 62, e202218659. DOI: 10.1002/anie.202218659). Yu Lan of Chongqing University and Lizhu Gao of Huaqiao University used an oxaloborolidinium catalyst to cyclize the unsaturated aldehyde 16 to the bicyclic ether 17 (Nature Commun. 2023, 14, 3511. DOI: 10.1038/s41467-023-39184-z). Xi Lu and Yao Fuo of the University of Science and Technology of China and Qiang Lu of Tsinghua University devised a protocol for coupling the dihydropyran 18 with the iodide 19, leading to the tetrahydropyran 20 (Angew. Chem. Int. Ed. 2023, 62, e202218544. DOI: 10.1002/anie.202218544). Jiang Wang and Hong Liu of the Shanghai Institute of Materia Medica reported a parallel investigation (Angew. Chem. Int. Ed. 2023, 62, e202300424. DOI: 10.1002/anie.202300424).

K. A. Woerpel of New York University observed that the coupling of the septanose acetate 21 with the ketene silyl acetal 22 led to the oxepane 23 with high diastereoselectivity (Org. Lett. 2023, 25, 152. DOI: 10.1021/acs.orglett.2c03963). Building on the work of Irving J. Borowitz of Yeshiva University (J. Org. Chem. 1968, 33, 2013. DOI: 10.1021/jo01269a067) and others, K. N. Houk of UCLA and Xin-Hua Duan and Li-Na Guo of Xi'an Jiaotong University effected the cleavage and concommitant coupling with trimethylsilyl cyanide of the hydroperoxide 24, leading to the macrolactone 25 (Chem. Sci. 2023, 14, 5220, DOI: 10.1039/D2SC06157K; Org. Lett. 2023, 25, 4329, DOI: 10.1021/acs.orglett.3c01427). Guang-Yao Ran of Chongqing Medical University assembled the macrolactone 28 by coupling the cyclic carbonate 27 with the enol lactone 26 (Org. Lett. 2023, 25, 2030. DOI: 10.1021/acs.orglett.3c00374). Boris M. Trofimov of the A. E. Favorsky Irkutsk Institute of Chemistry cyclized the alkyne 29 to the bicyclic ketal 30 (Org. Biomol. Chem. 2023, 21, 3183. DOI: 10.1039/D3OB00252G).

The polyene macrolide pentamycin (33), isolated from Streptomyces penticus, is a clinically effective antibiotic. Dirk Menche of the Universität Bonn prepared 33 by coupling the unprotected polyol 31 with the triene 32 (J. Am. Chem. Soc. 2023, 145, 10974. DOI: 10.1021/jacs.3c03011).

D. F. Taber, Org. Chem. Highlights 2024, January 8.