Four New Cuparene‐Type Sesquiterpenes from Flammulina velutipes

Flamvelutpenoids A–D (1–4), four new cuparene‐type sesquiterpenes, were isolated from the solid culture of Flammulina velutipes. Their structures were elucidated by NMR experiments. The absolute configurations of 1 and 2 were assigned via the circular dichroism data of the [Rh2(OCOCF3)4] complex, whereas that of C(3) of 3 was determined by applying the octant rule for the α,β‐unsaturated ketone moiety. Compounds 1–4 showed weak antibacterial activity against Escherichia coli, Bacillus subtilis, and methicillin‐resistant Staphylococcus aureus with MIC values larger than 100 μM.