ABSTRACT
This chapter focuses on the introduction of an additional substituent, such as a heteroatom or alkyl group, at the carbon atom next to the carbonyl group of a simple compound. The incorporation of nitrogen, through the utilization of imines, enamines, and hydrazones, has allowed for the introduction of a large number of chiral auxiliaries to be used in alkylation-type chemistry. The chapter discusses the general usage of this approach and its closely related asymmetric protonation methodology. Carbonyl compounds are versatile in synthesis due to their inherent ability to undergo nucleophilic addition and also to act as nucleophiles. In addition to carbon and oxygen nucleophiles, other useful groups and functionality can be introduced a to a carbonyl group through enolate or enol ether chemistry. The formation of an imine or other nitrogen analogs from a ketone allows incorporation of a chiral auxiliary which can be removed by hydrolysis after the alkylation.
