Organic Chemistry Portal
Organic Chemistry Highlights

Monday, November 27, 2023
Douglass F. Taber
University of Delaware

Organocatalyzed C-C Ring Construction: The Ikeuchi/Tanino Synthesis of Coriamytrin

Rong-Jie Chein of the Academia Sinica, Taipei used the known (S)-(thiolan-2-yl) diphenylmethanol benzyl ether to catalyze the Johnson-Corey-Chaykovsky cyclopropanation of the enone 1 with the allylic bromide 2 to give the cyclopropane 3 (J. Org. Chem. 2023, 88, 559. DOI: 10.1021/acs.joc.2c02573). Zhi-Xiang Yu of Peking University optimized the cyclization of the amide 4 to the cyclobutanone 5 (J. Am. Chem. Soc. 2023, 145, 9634. DOI: 10.1021/jacs.3c00685).

Wen-Hua Zheng of Nanjing University used a chiral oxaboraanthracene to mediate the enantioselective acylation of the prochiral diol 6 with the acid chloride 7, leading to the ester 8 (J. Am. Chem. Soc. 2023, 145, 8338. DOI: 10.1021/jacs.3c02331). Efraim Reyes and Jose L. Vicario of the University of the Basque Country and Pedro Merino of the Universidad de Zaragoza used a diphenylprolinol sily ether to rearrange the alkenyl cyclopropane 9 to the cyclopentene 10 (Angew. Chem. Int. Ed. 2023, 62, e202302416. DOI: 10.1002/anie.202302416). Song Ye of the Institute of Chemistry of the Chinese Academy of Sciences prepared the cyclopentane 12 by rearranging the prochiral lactone 11 with a chiral N-heterocyclic carbene (Org. Chem. Front. 2023, 10, 799. DOI: 10.1039/D2QO01721K). Bor-Cherng Hong of the National Chung Cheng University and Su-Ying Chien of the National Taiwan University showed that a diphenylprolinol sily ether cyclized the aldehyde 13 to the ester 14 (Org. Biomol. Chem. 2023, 21, 4200. DOI: 10.1039/D3OB00439B).

Matthew S. Sigman of the University of Utah, Scott J. Miller of Yale University and Song Lin of Cornell University designed a chiral aminoxyl radical that directed the trichloroisocyanuric acid oxidation of the diol 15 to the lactone 16 (Science 2023, 380, 706. DOI: 10.1126/science.adf6177). Hidetoshi Tokuyama of Tohoku University cyclized the homoallylic alcohol 17 with DABCO bromine complex and a binaphthol-based chiral phosphoric acid to give an intermediate that they then coupled with the allyl stannane 18, leading to the cyclohexane 19 containing a stereodefined quaternary center (Tetrahedron Lett. 2022, 101, 153906. DOI: 10.1016/j.tetlet.2022.153906). Jieping Zhu of the Ecole Polytechnique Fédérale de Lausanne also used a binaphthol-based chiral phosphoric acid to direct the course of the Diels-Alder cycloaddition of the enone 21 to the diene 20, leading to 22 (Angew. Chem. Int. Ed. 2023, 62, e202214925. DOI: 10.1002/anie.202214925). A chiral imidodiphosphorimidate successfully catalyzed the cyclization of the diene 23 to the cyclohexene 24, as reported by Christoph Schneider of the Universität Leipzig (Angew. Chem. Int. Ed. 2023, 62, e202302475. DOI: 10.1002/anie.202302475).

Furong Wang and Biaolin Yin of the South China University of Technology and Xiaohui Cao of Guangdong Pharmaceutical University showed that catalytic rose bengal directed the photocyclization of the imide 25 exclusively to the [4+2] product 26 (Adv. Synth. Catal. 2023, 365, 43. DOI: 10.1002/adsc.202201110). Sílvia Osuna of the Universitat de Girona and Bernhard Hauer of the University of Stuttgart redesigned squalene-hopene cyclase, leading to a whole cell system that efficiently converted homofarnesol 27 to the commercially-important ambroxide 28 (Angew. Chem. Int. Ed. 2023, 62, e202301607. DOI: 10.1002/anie.202301607).

Coriamyrtin (31) is a toxin found in high concentration in the berries of Coriaria myrtifolia, one of the most neurotoxic of the plants of the western Mediterranean. Kazutada Ikeuchi, now at Nagoya City University and Keiji Tanino of Hokkaido University showed that a benzimidazole-pyrrolidine cyclized the symmetrical diketone 29 with high diastereoselectivity, leading after oxidation to the carboxylic acid 30, that was carried on to 31 (Org. Lett. 2023, 25, 2751. DOI: 10.1021/acs.orglett.3c00249).

D. F. Taber, Org. Chem. Highlights 2023, November 27.