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Tandem Processes in C ‐Aryl Ketenes and Ketenimines Triggered by [1,5]‐Hydride‐Like Migration of an Acetalic Hydrogen Atom
Author(s) -
Vidal Angel,
MarinLuna Marta,
Alajarin Mateo
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201301501
Subject(s) - chemistry , tandem , ring (chemistry) , ketene , hydride , electrocyclic reaction , cascade reaction , aryl , thiophene , sequence (biology) , hydrogen atom , ketenimine , medicinal chemistry , aryne , hydrogen , stereochemistry , organic chemistry , catalysis , biochemistry , materials science , alkyl , composite material
Heating a range of suitably substituted diazoacetoacetates produced a family of 2‐(1,3‐dioxolan‐2‐yl)phenyl ketenes that, under thermal conditions, smoothly underwent a [1,5]‐H shift/6π‐electrocyclic ring‐closure sequence to give 1 H ‐2‐benzopyrans. The application of such processes to ketenes, produced by replacing the phenyl scaffolding with a thiophene ring, afforded thienopyrans. The aza‐Wittig reaction of these 2‐(1,3‐dioxolan‐2‐yl)phenyl and thienyl ketenes with N ‐aryliminophosphoranes provided analogous ketenimines that transform into the respective 1(2 H )isoquinolinones and thienopyridinones under similar thermal conditions, following the same type of cascade sequence.