Monday, January 13, 2025
Douglass F. Taber
University of Delaware
C-O Ring Construction: The Yu/Qin Synthesis of Nimbolide
Silvia Díez-González of Imperial College London cyclized the alkyne 1 to the enol ether 2 (Adv. Synth. Catal. 2024, 366, 806. DOI: 10.1002/adsc.202301181). Sébastien Prévost of the Ecole Polytechnique and Aurélien de la Torre of the Université Paris-Saclay constructed the tetrahydrofuran 5 by coupling the triol 3 with the sodium salt 4 of dimethyl malonate (Org. Lett. 2024, 26, 2393. DOI: 10.1021/acs.orglett.4c00495). Xin Mu and Bin Yang of Xi'an Jiaotong University and Jan-E. Bäckvall of Stockholm University carbonylated the allene 6 under oxidative conditions to give the lactone 7 (Org. Lett. 2024, 26, 2430. DOI: 10.1021/acs.orglett.4c00572). Hongchao Guo of China Agricultural University assembled the dihydrofuran 10 by combining the lactone 8 with acetyl chloride (9) (Org. Lett. 2024, 26, 2057. DOI: 10.1021/acs.orglett.4c00315).
Jolene P. Reid of the University of British Columbia used a imidodiphosphorimidate catalyst to mediate the preparation of the tetrahydropyran 13 by the combination of the diol 12 with the aldehyde 11 (ACS Catal. 2024, 14, 8518. DOI: 10.1021/acscatal.4c01494). Daniele Mazzarella and Luca Dell'Amico of the University of Padova used a Hayashi-Jřrgensen amine to mediate the electrolytic cylization of the aldeyde 14 to the tetrahydropyran 15 (Angew. Chem. Int. Ed. 2024, 63, e202401361. DOI: 10.1002/anie.202401361). Torsten Linker of the University of Potsdam devised the free-radical fragmentation of the sugar-derived cyclopropane 16 to the tetrahydropyran 17 (Chem. Eur. J. 2024, 30, e202302118. DOI: 10.1002/chem.202302118). Chulbom Lee of Seoul National University observed high diastereoselectivity in the decarboxylative cyclization of the carboxylic acid 18 to the tetrahydropyran 19 (Org. Lett. 2024, 26, 1067. DOI: 10.1021/acs.orglett.3c04305).
Jérôme Lacour of the University of Geneva prepared the tetrahydrooxepine 22 by coupling the oxetane 20 with ethyl diazoacetate 21 (Adv. Synth. Catal. 2024, 366, 1070. DOI: 10.1002/adsc.202301399). Tohru Oishi of Kyushu University observed that protected of the meso tetraol 23 with the camphor ketal 24 led to the ketal 25 with high diastereoselectivity.
Indrajeet Sharma of the University of Oklahoma cyclized the diol 26 to the oxetane 27 (ACS Catal. 2024, 14, 1292. DOI: 10.1021/acscatal.3c05040). William D. Wulff and Babak Borhan of the Michigan State University used a VANOL-derived imidodiphosphorimidate catalyst to mediate the oxidation of the enone 28 with the dibromohydantoin 29, leading to the spiroketal 30 (ACS Catal. 2024, 14, 426. DOI: 10.1021/acscatal.3c04773). Lin Peng of Shoyang University and Liang-Liang Wang of the Kunming Institute of Botany reported a related investigation (Org. Chem. Front. 2024, 11, 211. DOI: 10.1039/D3QO01615C).
Nimbolide (34), isolated from the neem tree Azadirachta indica of India, induces a profound degree of PARP1 trapping. Yonghao Yu, now at Columbia University, and Tian Qin of UT Southwestern Medical Center constructed the tetrahydrofuran of 34 by coupling the alcohol 31 with the tosylhydrazone 32 to give 33, presumably by way of the intermediate diazo cyclopentene. Free radical cyclization of 33 in fluorous solvent then delivered 34 (Nature Synth. 2024, 3, 378. DOI: 10.1038/s44160-023-00437-w).
D. F. Taber, Org. Chem. Highlights 2025, January 13.
URL: https://www.organic-chemistry.org/Highlights/2025/13January.shtm