Quinquevalent phosphorus acids
As in previous years, this chapter shows some of the most important achievements in 2016 in the area organophosphorus compounds containing three P–O bonds (phosphates), two P–O and one P–C bonds (phosphonates) as well as one P–O and two P–C bonds (phosphinates) in addition to the PO bond, one of the strongest heteroatom bonds in chemistry. Each of the main sections has been divided in the same way, covering synthesis, reactions and biological aspects. In all three sections, there has been a good coverage of various subjects, like new reagents, new methods of synthesis, total and stereocontrolled syntheses, multicomponent reactions and biological investigations. Achievements in synthesis and applications of phosphoricacids as catalysts, inroduced in the Chapter for the first time in 2009, recorded a further quantitative growth. This year, the area devoted to phosphoric and phosphonic acids and their derivatives showed a further, continuing progress and dominated traditionally over a small subsection of phosphinic acids and derivatives.