Abstract

In the long history of human development, natural products have been an important source of medicines for human beings to fight against diseases. Early humans did not fully understand these drugs, but according to the experience, various drugs with physiological activity have been recorded and handed down, such as the well-known “traditional Chinese medicine”. With the improvement of the level of cognition of organic chemistry, human discovered that the important material for the treatment of diseases is the active natural products. Because of their low natural abandance and time-consuming separation properties, synthesis is often used as an important way to obtain active natural products, and total synthesis of natural products has gradually been becoming an important research direction in the field of organic chemistry.

Cyclopianes are rare tetracyclic diterpenes, bearing a highly fused and strained 6/5/5/5 ring system embedded up to 8 consecutive stereocenters, in which there are four quaternary carbon centers which installed a serious impediment to its synthetic progress.1 Natural products conidiogenone (1) and conidiogenol (2) were first isolated by Sterner in 2002, after which more than 20 analogues (Scheme 1-1) were discovered from fungi, sponges, and soft corals, and many of them exhibited a wide range of biological activities. 

1 and 2 displayed potent activity for induction of conidiogenesis in the fermentation of Penicillium cyclopium, which may become novel leading compound for the study of the morphogenetic envent. Conidiogenone B (3) exhibited high antibacterial activity against methicillin-resistant Staphylococcus aureus, Pseudomonas fluorescens, P.aeruginosa, and S. epidermidis. Conidiogenone C (4) showed high cytotoxicity against HL60 cell.2 

Scheme. 1-1 Representative structures of cyclopiane-type diterpenes

Reference:

(1) Xu, B.; Xun, W.; Su, S.; Zhai, H. Angew. Chem. Int. Ed. 2020, 59, 16475-16479.

(2) Roncal, T.; Cordobés, S.; Ugalde, U.; He, Y.; Sterner, O. Tetrahedron Lett. 2002, 43, 6799-6802.