Endophyte inspired chemical diversity from beta-caryophyllene†
The natural product (−)-β-caryophyllene is considered as an ideal initiator to generate diverse scaffolds by transannular cyclization due to its macrocyclic structure and abundant availability in nature. An endophytic strain Aspergillus tubingensis KJ-9 was screened in our lab to catalyse remodeling of the β-caryophyllene skeleton. In the fermentation, macrocyclic β-caryophyllene was remodeled into a series of natural product-like polycyclic compounds with unusual diverse skeletons (1–7). Their structures, including absolute configuration, were elucidated by several spectroscopic methods (1D & 2D NMR, HRMS, ECD and X-ray diffraction). Especially, scaffolds 1 and 3 were not found in acid-catalysed products before. Our findings demonstrated the potential of endophytic fungi for catalyzing macrocyclic compounds into diverse products.