A formal synthesis of (−)-haliclonin A, isolated from the marine sponge Haliclona sp. in Korea, is described. The key feature of the synthesis includes the highly stereoselective tandem radical reaction to construct the azabicyclo[3.3.1]­nonane core and the enantioselective formation of an all-carbon quaternary center via the Pd-mediated deracemization.

Enantioselective formation of cyclohexene derivatives bearing an all‐carbon quaternary stereogenic center is described. The racemic cyclohexenes are readily transformed to chiral substituted cyclohexenes in good yield with excellent enantioselectivity and diastereoselectivity by a palladium‐mediated deracemization. The resulting products are promising synthetic intermediates of biologically active natural products. This protocol provides us with a new entry to the concise and scalable synthesis of multifunctionalized compounds.

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