Covering: 2008–2010 This report describes the recent applications of hypervalent iodine reagents in the total synthesis of natural products. The large diversity of high-yielding and chemoselective reactions that can be achieved, even for highly functionalized molecules, is summarized, demonstrating that hypervalent iodine reagents have become an essential tool in synthetic organic chemistry.

Hypervalent iodine reagents constitute a powerful tool in modern synthetic organic chemistry, promoting several important reactions. One such reaction is the ring contraction of cycloalkenes and cycloalkanones promoted by iodine(III) compounds, such as iodobenzene diacetate, iodosylbenzene, iodotoluene difluoride, and [hydroxy(tosyloxy)- iodo]benzene (Koser ́s reagent). This review covers all the literature related to the ring contraction of cyclic ketones and olefins promoted by iodine(III) species.

A new method for the electrophilic α-alkynylation of ketones was developed using hypervalent iodine under mild and metal-free conditions. Carbonyl compounds containing an α-acetylene group were obtained in good to excellent yields for several ketones using 1-[(trimethylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one (TMS-EBX) as an alkynylation agent in the presence of t-BuOK and TBAF in THF as solvent. Under the same conditions, an aldehyde was alkynylated.