Metal-free tandem reaction synthesis of spiro-cyclopropyl fused pyrazolin-5-one derivatives†
Abstract
A highly efficient cascade annulation approach was developed for the synthesis of novel spiro-cyclopropyl fused pyrazolin-5-ones from pyrazole-3-ketone substrates and two-component sulfur ylides in an acidic environment. This metal-free one-pot reaction has the advantages of easily available active materials, simple operation and brand new spirocyclic skeletons.