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Synthesis of Fused Indoline‐Cyclobutanone Derivatives via an Intramolecular [2+2] Cycloaddition
Author(s) -
Neyyappadath Rifahath M.,
Greenhalgh Mark D.,
Cordes David B.,
Slawin Alexandra M. Z.,
Smith Andrew D.
Publication year - 2019
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.201900326
Subject(s) - chemistry , ketene , cycloaddition , cyclobutanone , indoline , intramolecular force , ring (chemistry) , tertiary amine , intramolecular reaction , combinatorial chemistry , stereochemistry , catalysis , organic chemistry
A serendipitously‐discovered process for the synthesis of heterocyclic products containing a novel fused indoline‐cyclobutanone ring system is reported. This process is believed to take place through in situ generation of a ketene intermediate, followed by intramolecular [2+2] cycloaddition with a pendant enamide. The formation of a ketene intermediate in this process is significant as the reaction conditions employed are analogous to those commonly used in tertiary amine Lewis base catalysis, where the potential intermediacy of ketenes is an important consideration that is often overlooked.