Asymmetric total synthesis of (+)-fusariumin and (+)-sporotricale methyl ether: exploration of a Cu(i) catalysed regiodivergent cascade cyclization strategy

Abstract

Asymmetric total synthesis of the isocoumarin-based natural product (+)-fusariumin was achieved through Cu(I) catalysed 6-endo-dig cyclization as a key step. The synthesis of the phthalide-based natural product sporotricale methyl ether was also achieved through an alternative 5-exo-dig cyclization protocol. 2-Bromo-4,6-dimethoxybenzoic acid and an appropriately substituted terminal alkyne were used as reaction partners for the crucial construction of the desired isocoumarin and phthalide frameworks present in the target structures.