Abstract
Few examples of [4 + 2] cycloaddition with unmasked ortho-benzoquinones (UMOBs) as carbodiene have been reported in complex molecule synthesis. Herein we report that this cycloaddition with podocarpane-type UMOB was developed and applied to construct fully functionalized bicyclo[2.2.2]octanes. Based on this methodology, divergent total syntheses of atisane-type diterpenoids, including (±)-crotobarin, crotogoudin, atisane-3β,16α-diol, and 16S,17-dihydroxy-atisan-3-one, were accomplished in 14, 14, 12, and 16 steps, respectively. Key elements in these total syntheses include: (1) FeCl3-catalyzed cationic cascade cyclization to construct podocarpane-type skeleton; (2) Mn(III)/Co(II)-catalyzed radical hydroxylation of alkene with high regio-, diastereo-, and chemoselectivities; (3) and a ketal-deprotection/lactone-opening/deprotonation/lactonization cascade. Additionally, the synthetic utility of the fully functionalized bicyclo[2.2.2]octane framework was further elucidated by applying ring distortion strategy to afford different skeleton-rearranged natural product-like compounds.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
