C-O Ring Construction: The Feng/Liu Synthesis of Goniochelienactone

Susannah C. Coote of Lancaster University assembled the oxetane 3 by the photochemical addition of citraconic anhydride 2 to cyclohexanone (1) (Chem. Commun. 2023, 59, 784. DOI: 10.1039/D2CC06459F). Mattia Silvi of the University of Nottingham prepared the oxetane 6 by the photochemically-promoted coupling of the alcohol 4 with the vinyl sulfonium salt 5, followed by base (J. Am. Chem. Soc. 2023, 145, 15688. DOI: 10.1021/jacs.3c04891).

Shyam Sathyamoorthi of the University of Kansas cyclized the aziridine 7 to the tetrahydrofuran 8 (J. Org. Chem. 2023, 88, 9136. DOI: 10.1021/acs.joc.3c00763). Sandipan Halder of the Visvesvaraya National Institute of Technology used a ketimine catalyst to couple epichlorohydrin 10 with the bis nitrile 9, leading to the tetrahydrofuran 11 with high diastereocontrol (J. Org. Chem. 2023, 88, 12872. DOI: 10.1021/acs.joc.2c00902). Yong Jian Zhang of Shanghai Jiao Tong University devised the cascade cyclization of the enone 12 with the racemic carbonate 13, leading to the dihydrofuran 14 in high ee (J. Org. Chem. 2023, 88, 12100. DOI: 10.1021/acs.joc.3c00976). Michael J. Krische of the University of Texas observed clean inversion in the cyclization of the epoxide 15 to the highly-substituted tetrahydrofuran 16 (Org. Lett. 2023, 25, 6763. DOI: 10.1021/acs.orglett.3c02699).

Ramu Sridhar Perali of the University of Hyderabad showed that the readily-prepared DMDO was an effective reagent for the initiation of the Mislow rearrangement of the allylic sulfide 17 to the alcohol 18 (J. Org. Chem. 2023, 88, 12105. DOI: 10.1021/acs.joc.3c01067). Xu-Ge Liu of Hennan University and Honggen Wang of Sun Yat-Sen University prepared the dihydropyran 21 by coupling the iodoalkene 19 with the Katritzky N-alkyl pyridinium salt 20 (Org. Lett. 2023, 25, 5022. DOI: 10.1021/acs.orglett.3c01691). Zhong-Lin Wei of Jilin University and Wei-Wei Liao of the Shanghai Institute of Organic Chemistry used a quinine squaramide to direct the absolute sense of the tandem Claisen rearrangement/oxy-Michael rearrangement of the nitroalkene 22 to the dihydropyran 23 (Org. Lett. 2023, 25, 6434. DOI: 10.1021/acs.orglett.3c02461). Shi-Kun Jia of Zhengzhou University also achieved high enantiomeric excess in the coupling of the prochiral cyclohexadienone 24 with the α-hydroxy ketone 25, leading to the bicyclic enone 26 (Org. Chem. Front. 2023, 10, 4516. DOI: 10.1039/D3QO00925D).

Kosuke Higashida and Masaya Sawamura of Hokkaido University achieved high geometric control in the cyclization of the alkyne 27 to the lactone 28 (Chem. Eur. J. 2023, 29, e202301917. DOI: 10.1002/chem.202301917). Xiaohua Xu and Zhong Jin of Nankai University and Jin-Quan Yu of Scripps/La Jolla effected oxidative conversion of the acrylate 29 to the meta-substituted macrocycle 30 (Chem. Sci. 2023, 14, 8279. DOI: 10.1039/D3SC01670F).

Goniochelienactone (34) was isolated from the South Asian tree Goniothalamus cheliensis, extracts of which have been used in traditional medicine. Fu Feng of Hubei Minzu University and Jun Liu of the Research Center for Eco-Environmental Sciences of the Chinese Academy of Science developed an expeditious approach to 34 based on cross metathesis of the allylic alcohol 31 with methyl acrylate (32), followed by diastereoselective cyclization to the tetrahydropyran 33 (Eur. J. Org. Chem. 2023, 26, e202300749. DOI: 10.1002/ejoc.202300749).