Abstract by Garrison Nickel
Chemistry and Biochemistry
Microwave-promoted cyclization of oxime ethers
The cyclization of iminyl radicals is a powerful process for creating cyclic imines and pyrroles. Iminyl radicals are formed upon microwave heating of O-phenyl oxime ethers, eliminating the need for heavy metal, peroxide, or photoredox catalysts. These iminyl radicals can be captured after cyclization by a variety of radical traps, allowing for the synthesis of many functionalized adducts via a radical cascade process. We demonstrate the use of several radical traps in the formation of new carbon-carbon and carbon-oxygen bonds in the cyclized products. Additionally, we demonstrate that installing a thiophenyl group as a radical acceptor on the carbon beta to the cyclization site allows for iminyl radical cyclizations to proceed without addition of an external radical trap.