Enantioselective Lactonization by π-Acid-Catalyzed Allylic Substitution: A Complement to π-Allylmetal Chemistry
Arun Raj Kizhakkayil Mangadan1, Ji Liu1, Aaron Aponick1
1Florida Center for Heterocyclic Compounds and, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611, USA.
Abstract:
Asymmetric allylic alkylation (AAA) is a powerful method for the formation of highly useful, non-racemic allylic compounds. Here we present a complementary enantioselective process that generates allylic lactones via π-acid catalysis. More specifically, a catalytic enantioselective dehydrative lactonization of allylic alcohols using a novel PdII -catalyst containing the imidazole-based P,N-ligand (S)-StackPhos is reported. The high-yielding reactions are operationally simple to perform with enantioselectivities up to 99 % ee. This strategy facilitates the replacement of a poor leaving group with what would ostensibly be a better leaving group in the product avoiding complications arising from racemization by equilibration.
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