Sulfur Activated α-Methylene Reagents in Asymmetric Catalysis

The use of active methylene reagents in asymmetric catalysis allows interesting and wide synthetic applications for the preparation of highly elaborated enantioenriched compounds. In this review, the chemistry in which sulfur groups, such as a sulfone or more recently even a sulfoxide, in the reagent is utilized to activate the α-methylene position towards either an electrophilic or a nucleophilic attack is compiled. The review is divided into three sections that expose these two activation approaches and the combination of both, and, in each part, the examples are classified according to the reaction type involved. Moreover, the possibility of further functionalization of the products in has also been exemplified.