In past two decades, hypervalent iodine chemistry has developed as an important tool in synthetic and natural product chemistry. Hypervalent iodine reagents have been applied to a variety of reactions such as oxidations, oxidative cyclizations, and rearrangements. Many synthetic transformations can also be achieved by using these reagents as catalysts. Recently, chiral hypervalent iodine reagents have been used for synthetically valuable stereoselective transformations. This chapter describes oxidative functionalizations with hypervalent iodine(III) and (V) reagents as well as hypervalent bromine compounds. © 2014 Elsevier Ltd. All rights reserved.