Research into the development of new catalytic modes, as exemplified by the rapidly expanding field of organocatalysis, has led to the efficient synthesis of polyfunctionalized molecules with routinely high levels of stereocontrol. This chapter focuses specifically on formal [2+2] cycloadditions catalyzed by Lewis bases, with an exclusive focus on those processes that have been rendered asymmetric. Detailed analysis of reaction design, mechanism, and product utility are made for a range of important four-membered heterocyclic classes, beginning with β-lactams and β-lactones before further expanding to more elaborate architectures, such as aza-β-lactams, β-sultams, and β-sultones. It demonstrates the role and development of Lewis base catalysts in asymmetric ketene homodimerization, the potential utility of such stereodefined polyketide scaffolds, and the emerging field of asymmetric ketene heterodimerization.
|Title of host publication
|Methods and Applications of Cycloaddition Reactions in Organic Syntheses
|Number of pages
|Published - 10 Feb 2014
- Asymmetric formal [2+2] cycloadditions
- Ketene dimers
- Lewis base