ABSTRACT

This chapter covers reactions in which a stereogenic sp3 center is inverted or undergoes a substitution reaction. To control the stereochemical outcome of a substitution reaction, an SN2 mechanism usually has to be used. As a consequence, inversion of configuration is usually observed, although in some reactions two sequential substitutions can occur to give the overall appearance of retention. The use of an SN2 reaction necessitates the establishment of the stereogenic center in the reactant. When an isolated center undergoes this type of reaction, it is usually to correct stereochemistry.