Tandem (2 + 2) Annulation/Retro-4π Electrocyclization/Imino-Nazarov Cyclization Reaction of <i>p</i>-Quinone Methides with Ynamides: Expeditious Construction of Functionalized Aminoindenes
Ke‐Yin Yu, Yu‐Hua Deng, Xiao‐Min Ge, Xian‐Tao An, Peng-Fei Shu, Ye‐Xing Cao, Xian‐He Zhao, Chun‐An Fan
Abstract
A new tandem annulation of p-quinone methides (p-QMs) with ynamides is described. This cascade reaction features a unique combination of (2 + 2) annulation, retro-4π electrocyclization, and imino-Nazarov cyclization, wherein vinyl p-quinone methides (p-VQMs) as one of the key intermediates have been identified chemically. Significantly, an unusual structural reconstruction of p-QMs involving the cleavage of the C5–C6 bond and the late-stage formation of the C4–C6 bond is involved, leading to a methodology development for the construction of functionalized aminoindenes.
Topics & Concepts
AnnulationChemistryTandemQuinoneCascade reactionCascadeCombinatorial chemistryCleavage (geology)StereochemistryOrganic chemistryCatalysisGeotechnical engineeringFracture (geology)EngineeringMaterials scienceChromatographyComposite materialSynthesis of Indole DerivativesCarbohydrate Chemistry and SynthesisAxial and Atropisomeric Chirality Synthesis