Formation of allylated quaternary carbon centers via C–O/C–O bond fragmentation of oxalates and allyl carbonates†
Abstract
Disclosed herein emphasizes Fe-promoted cross-electrophile allylation of tertiary alkyl oxalates with allyl carbonates that generates all C(sp3)–quaternary centers. The reaction involves fragmentation of tertiary alkyl oxalate C–O bonds to give tertiary alkyl radical intermediates, addition of the radicals to less hindered alkene terminals, and subsequent cleavage of the allyl C–O bonds. Allylation with 2-aryl substituted allyl carbonates was mediated by Zn/MgCl2, and Fe is used to promote the radical addition efficiency. By introduction of activated alkenes, a three-component radical cascade reaction took place.