Reagents for Carbonyl Methylenation in Organic Synthesis

The methylenation of carbonyl compounds in the areas of natural and non-natural products chemistry is described herein. Phosphorus, sulfur and silicon-based reagents are compared with more recent systems based on boron, zinc and titanium and the relative merits of each reagent are discussed. Particular attention is paid to methods, which can overcome the problems associated with sterically hindered or enolizable aldehydes and ketones.