Total Synthesis of (−)-Ceforalide B and (−)-Cephanolides B–D

作者：Zhongliu Sun, Xin Fan, Zezhong Sun, Zhijie Li, Lihua Niu, Hao Guo, Zhiqiang Ren, Yunxia Wang, Xiangdong Hu · 发表于：Organic Letters · 年份：2022 · DOI：10.1021/acs.orglett.2c02679 · 被引用次数：29 · 研究领域：Biological Activity of Diterpenoids and Biflavonoids、Natural product bioactivities and synthesis、Traditional and Medicinal Uses of Annonaceae

(−)-Ceforalide B ( 1 ) and (−)-cephanolides B–D ( 2 – 4 ) are benzenoid cephanolide diterpenoids possessing the same pentacyclic skeleton, which contains three C 13 –C 15 substituent patterns and different benzylic oxidation states. An olefination/6π-electrocyclization/oxidative aromatization cascade has been verified as divergent access to three C 13 –C 15 patterns. The benzylic aerobic oxidations enabled by the Co(OAc) 2 ·4H 2 O/bromide salt/O 2 /PPh 3 / N -hydroxyphthalimide system have been developed to deliver expected site-selectivity and different oxidation states. Through the divergent strategy, total synthesis of (−)-ceforalide B and (−)-cephanolides B–D is accomplished.