A New and Mild System for the Generation of Nonstabilized Carbonyl Ylides: Synthetically Practical Use in Reactions with Electron-Deficient Dipolarophiles
Thioacetals are selectively transformed into two types of terminal olefins, one with one-carbon homologation and the other with two-carbon homologation, by treatment with a titanocene(II) species under ethylene. The mode of the reaction is controlled by changing the ligands coordinated to titanocene(II).
Modified Cyclization of Enantio-enriched a-Homoallyloxyalkyllithiums Generated by Sn-Li Transmetallation: Effects of Additives and Structural Requirement