Chirality Transfer and Asymmetric Catalysis: Two Strategies toward the Enantioselective Formal Total Synthesis of
Phil C Knutson1, Haofan Ji1, Christopher M Harrington1
1Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.
Abstract:
Two strategies are described en route to an enantioselective total synthesis of gelsenicine. One approach centers on a chirality transfer cycloisomerization that ultimately fell short. Separately, an asymmetric catalysis route utilizing bisphosphine-gold-catalyzed cycloisomerization was pursued. A catalytic system was identified that provided a synthetic intermediate in our Gelsemium alkaloid syntheses in high enantiopurity and with absolute configuration determined by electronic circular dichroism, thus representing an enantioselective formal total synthesis of (+)-gelsenicine.
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