Stereoselective Synthesis of Indoline-Fused Cyclobutanes via Dual Functionalization of Alkynyl Diazo Carboxylates
Priya Sharma1, Akashdeep Sharma1, Nishant Joon1
1Department of Chemistry, Indian Institute of Technology Jammu, PO Nagrota, Jammu, Jammu and Kashmir 181221, India.
Abstract:
We report stereoselective synthesis of indoline-fused cyclobutanes through dual functionalization of alkynyl diazoacetates. The development proceeds through Rh-catalyzed insertion of alkynyl carbenes into 2-alkenyl anilines, followed by a base-promoted alkynoate-allenoate isomerization and cycloaddition cascade. The protocol expands the synthetic utility of alkynyl diazoacetates and provides a broad range of indoline-fused cyclobutanes with excellent yields and stereoselectivity (up to 97% yield and >20:1 dr). The synthetic applications of densely functionalized indoline scaffolds are shown toward obtaining useful motifs.
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