Dedicated to Prof. Dr. İlker Özkan on the occasion of his 70th birthday
Abstract
A facile, efficient and unprecedented method for the synthesis of spiro-2H-pyrroles is reported. When reacted with 1-ethynylcyclohexylamine, α,β-alkynic ketones
produced cyclohexane-embedded N-propargylic β-enaminones, which in the presence of cesium carbonate underwent nucleophilic
cyclization to afford 1-azaspiro[4.5]deca-1,3-diene derivatives in good to excellent
yields. This cyclization was found to be general for a variety of cyclohexane-embedded
N-propargylic β-enaminones and demonstrated good tolerance to a broad range of aliphatic,
aromatic and heteroaromatic groups with electron-withdrawing and electron-donating
substituents. The decoration of pyrrole compounds with a spiro framework may exhibit
potential for the synthesis of molecules of pharmacological interest.
Key words
pyrroles - 2
H-pyrroles -
N-propargylic β-enaminones - spiro compounds - nucleophilic cyclization