An efficient and stereoselective synthesis of obolactone via modified Evans' Aldol protocol

Stereocontrolled total synthesis of obolactone was achieved from trans-cinnamaldehyde. The key steps in this synthetic sequence are a asymmetric Mukaiyama Aldol, a Crimmins' modified Evans' Aldol reaction to introduce C2′ stereocentre, a nucleophilic addition of potassium salt of mono methyl malonate, a Z-olefination using Andos' modified Horner-Wadsworth-Emmons reagent to introduce Z-olefin at C3, C4 in the final lactone skeleton, and a tandem deprotection and lactonization.

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