Isothiourea Catalysis – New Opportunities for Asymmetric Synthesis

The use of chiral isothioureas to promote enantio- and diastereoselective organocatalytic transformations has rapidly developed in recent years. This chapter gives an overview of the enantioselective methods developed in this area, describing the use of chiral isothioureas to generate a number of synthetic intermediates from a range of readily accessible starting materials. The use of an isothiourea can result in the formation of a range of reaction intermediates (acyl ammonium, α,β-unsaturated acyl ammonium, ammonium enolate, and silyl ammonium) with typical processes that proceed through each of these intermediates described. The breadth of reactivity observed, including a number of approaches to ensuring catalyst turnover, will be discussed.