The Thia-Michael Reactivity of Zerumbone and Related Cross-Conjugated Dienones: Disentangling Stoichiometry, Regiochemistry, and Addition Mode with an NMR-Spectroscopy-Based Cysteamine Assay
The cross-conjugated and electrophilic dienonesystem of the humulane sesquiterpene zerumbone (1a) was modified by E/Z photochemical isomerization and/or by removal of homoconjugation with the isolated endocyclic double bond of the medium-sized ring. The site (C-6/C-9), mode (transient or irreversible), stoichiometry (single or twofold), and comparative rates of thiol addition were evaluated using
Putative Biomimetic Route to 8-Oxabicyclo[3.2.1]octane Motif from a Humulene Sesquiterpenoid Zerumbone
作者:Kollery S. Veena、Greeshma Gopalan、Murali Madhukrishnan、Sunil Varughese、Kokkuvayil Vasu Radhakrishnan、Ravi S. Lankalapalli
DOI:10.1021/acs.orglett.0c02220
日期:2020.8.21
An approach to expand the diversity of terpenes to novel polycyclic skeletons with contiguous stereogenic centers is described. An unprecedented 8-oxabicyclo[3.2.1]octane motif was obtained in quantitative yield by photoirradiation of zerumbone in the presence of a catalytic amount of Lewis acid. The vital role of light in the isomerization of double bonds in zerumbone, which ensued cyclization via