Hypercohin A, a new polycyclic polyprenylated acylphloroglucinol possessing an unusual bicyclo[5.3.1]hendecane core from Hypericum cohaerens

Hypercohin A (1), an unprecedented polycyclic polyprenylated acylphloroglucinol featuring with an unusual bicyclo[5.3.1]hendecane core, was isolated from Hypericum cohaerens. Its structure and absolute configurations were elucidated by extensive NMR methods and crystal X-ray diffractions of its p-bromobenzoate ester (2).