Reactions of Alkenes: The Christmann Synthesis of Spongidine A
Young Ho Rhee of POSTECH showed that 2 could be prepared by the migration the alkene of 1 (Org. Lett. 2020, 22, 2178. DOI: 10.1021/acs.orglett.0c00279). Yian Shi of Colorado State University accomplished the selective conversion of 3 to 4 (Org. Lett. 2020, 22, 1868. DOI: 10.1021/acs.orglett.0c00168). Wanxiang Zhao of Hunan University effected the migratory hydroboration of the alkene of 5, leading to 6 (Angew. Chem. Int. Ed. 2020, 59, 2360. DOI: 10.1002/anie.201913281). Jian-Ping Qu of Nanjing Tech University and Yan-Biao Kang of the University of Science and Technology of China observed high regioselectivity in the Wacker oxidation of 7, leading to 8 (Org. Lett. 2020, 22 965. DOI: 10.1021/acs.orglett.9b04503).
Wei Li of the University of Toledo incorporated benzylamine 10 in the oxidative cyclization of 9, to give the hydroxylated lactam 11 (Org. Lett. 2020, 22, 884. DOI: 10.1021/acs.orglett.9b04432). Christoforos G. Kokotos of the National and Kapodistrian University of Athens showed that the hydroacylation of 13 with 12 led to the linear product 14 (Angew. Chem. Int. Ed. 2020, 59, 1735. DOI: 10.1002/anie.201912214). Josep Bonjoch and Ben Bradshaw of the Universitat de Barcelona assembled 17 by adding the radical derived from 15 to the tosylhydrazone 16 (Org. Lett. 2020, 22, 684. DOI: 10.1021/acs.orglett.9b04459). Frank Glorius of the Westfälische Wilhelms-Universität Münster effected the decarboxylative addition of the elements of 18 to 19, leading to 20 (Angew. Chem. Int. Ed. 2020, 59, 3172. DOI: 10.1002/anie.201912907).
Tomislav Rovis of Columbia University observed high regioselectivity in the preparation of 23 by the addition of 22 to 21 (Angew. Chem. Int. Ed. 2020, 59, 4965. DOI: 10.1002/anie.201916332). Chen Zhu of Soochow University also formed two carbon-carbon bonds in the addition of 25 to 24 to give 26 (Angew. Chem. Int. Ed. 2019, 58, 17646. DOI: 10.1002/anie.201910514). Gavin Chit Tsui of the Chinese University of Hong Kong reported related results (Org. Lett. 2019, 21, 8625. DOI: 10.1021/acs.orglett.9b03230). Professor Zhu also achieved the addition of 28 to 27, leading to 29 (Angew. Chem. Int. Ed. 2020, 59, 8195. DOI: 10.1002/anie.201915837). Xiao-Feng Wu of the Universität Rostock effected the carbonylative coupling of 30 with 31, leading to 32 (Angew. Chem. Int. Ed. 2020, 59, 10451. DOI: 10.1002/anie.202002714).
Spongidine A (36), isolated from a sponge harvested near the coast of Tongoa, shows potent inhibitory activity against soluble phospholipase A. In the course of a synthesis of 36 from sclareolide, Mathias Christmann of the Freie Universität Berlin assembled 35 by the Suzuki coupling of 34 with the borane derived from 33 (Org. Lett. 2020, 22, 552. DOI: 10.1021/acs.orglett.9b04315).