Complete Synthesis Of Mansonone E

Squatate esters have unique structures and properties, and are widely used in the synthesis of 1,4-dicarbonyl and 1,3-dicarbonyl. Quinones are widely existed in natural products. Many quinone natural products have good biological activities and have exhibited the high value for new drug research. Moore-Liebeskind cyclization reaction in which squatate esters is used as starting material is a simple and efficient method for the synthesis of quinones.Mansonone E which is a tricyclic sesquiterpenoid containing a 1,2-naphthoquinone moiety was first isolated from the heartwood sawdust of Mansonia Altissima and then from many elms. Mansonone E showed antibacterial activity and significant cytotoxic activities against many human cancer cell lines. The existing route for the synthesis of mansonone E is long and the overall yield is low. In this paper, the synthesis of mansonone E was completed in six steps and 34% overall yield from commercially available starting materials. The combination of Moore-Liebeskind cyclization reaction and intramolecular 1,3-alkoxy exchange provided a facile route to synthesize the 1,2-naphthoquinone containing tricyclic structure of mansonone E.