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Updated: Aug 12, 2025

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
Visible-light induced metal-free intramolecular reductive cyclisations of ketones with alkynes and allenes
Nana Tang1, Raphael J Zachmann1, Hui Xie1
1Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, Freiburg im Breisgau 79104, Germany. bernhard.breit@chemie.uni-freiburg.de.
Abstract:
A visible-light-induced, intramolecular, reductive cyclisation of ketones with an unsaturated hydrocarbon moiety was developed. In contrast to conventional protocols requiring resource precious or hazardous metal sources, this method enables facile access to ketyl radicals under metal-free and mild reaction conditions. By polarity-reversed, ketyl radical hydroalkoxylation of alkynes and allenes, a variety of five-membered (hetero-)cyclic products were generated in good yields with good to excellent stereoselectivities. The embedded homoallylic tertiary alcohol could be transformed into other useful functionalities, highlighting the synthetic utility of this reaction. This efficient and sustainable ketyl-alkyne/allene cross coupling also features broad functional group tolerance and scalability.
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