Blue LED Irradiation of Iodonium Ylides Gives Diradical Intermediates for Efficient Metal‐free Cyclopropanation with Alkenes
作者:Tristan Chidley、Islam Jameel、Shafa Rizwan、Philippe A. Peixoto、Laurent Pouységu、Stéphane Quideau、W. Scott Hopkins、Graham K. Murphy
DOI:10.1002/anie.201908994
日期:2019.11.18
A facile and highly chemoselective synthesis of doubly activated cyclopropanes is reported where mixtures of alkenes and β-dicarbonyl-derived iodoniumylides are irradiated with light from blue LEDs. This metal-free synthesis gives cyclopropanes in yields up to 96 %, is operative with cyclic and acyclic ylides, and proceeds with a variety of electronically-diverse alkenes. Computational analysis explains
Thermally Induced Cycloadditions of Donor/Acceptor Carbenes
作者:Stephanie R. Ovalles、Jørn H. Hansen、Huw M. L. Davies
DOI:10.1021/ol201628d
日期:2011.8.19
The thermal decomposition of aryldiazoacetates and aryldiazoketones in the absence of a catalyst leads to synthetically useful transformations. The thermal reaction of aryldiazoacetates with alkenes generates cyclopropanes in 68-97% yield and with good diastereoselectivity (up to 19:1 dr) when the aryl substituent is electron-rich. The thermal reaction of aryldiazoketones with alkenes generated cyclobutanones in 71-94% yield and with good diastereocontrol (>= 9:1 dr).