Formation of spiro indane derivatives from hydroxy lactams derived from N-(1-phenylethyl)-phthalimide and -pyridine-2,3-dicarboximide

Abstract

Spiro[indane-1,7′-pyrrolo[3,4-b]pyridin]-5′-ones 18–22 are formed by acid-catalysed rearrangement from 7-aryl-7-hydroxy-6-(1-phenylethyl)-6,7-dihydropyrrolo[3,4-b]pyridin-5-ones. Further spiro indanes 39, 43 and 44 and spiro naphthalenes 41, 42, 45 and 46 are obtained from 3-(ω-phenylalkyl)-3-hydroxy-2-(1-phenylethyl)isoindolin-1-ones or from 7-(ω-phenylalkyl)-7-hydroxy-6-(1-phenylethyl)-6,7-dihydropyrrolo[3,4-b]pyridin-5-ones viaα,α-cyclisation of N-acyliminium ion intermediates.