γ-Substituted Allenic Amides in the Phosphine-Catalyzed Enantioselective Higher Order Cycloaddition with Azaheptafulvenes
Rubén Manzano, Aketza Romaniega, Liher Prieto, Estíbaliz Díaz, Efraím Reyes, Uxue Uria, Luisa Carrillo, José L. Vicário
Abstract
Racemic γ-substituted allenes undergo enantioselective higher order [8 + 2]-cycloaddition with azaheptafulvenes using a chiral amino acid derived amidophosphine as catalyst, providing the corresponding azaazulenoid cycloadducts with excellent levels of regio-, diastereo-, and enantioselectivities. In this reaction, the activated allylic phosphonium ylide intermediate participates as the C2-component of the reaction, in contrast to the conventional reactivity of this type of zwitterionic intermediates as C3-components in cycloaddition reactions.
Topics & Concepts
CycloadditionChemistryEnantioselective synthesisPhosphoniumCatalysisPhosphineYlideReactivity (psychology)Allylic rearrangementMedicinal chemistryOrganic chemistryPathologyAlternative medicineMedicineAsymmetric Synthesis and CatalysisCyclopropane Reaction MechanismsSynthesis and Catalytic Reactions