First Characterization of a Titanium Enolate Radical Cation in Solution: Carbon-Carbon Bond Formation and the Kinetics of the Mesolytic Ti-O Bond Cleavage

摘要

Ever since their first successful use in 1981 titanium enolates have had an important standing as versatile synthetic carbon nucleophiles in stereoselective aldol and Michael reactions, in particular because they allow for higher stereoselectivites than lithium enolates. Most importantly, the incorporation of chiral ligands at the titanium center opened the way for erian tioselective aldol reactions with excellent ee values. Surprisingly, the uinpolung of titanium enolates through one-electron oxidations is hitherto completely unknown, although such radical cations should offer interesting electrophilic features that could be exploited in carbon carbon bond formation, quite in analogy to the recent chemism of silyi and stannyl enol ether radical cations.