text: One of the most developed areas of phosphaalkyne chemistry is that of cycloadditions. Like other multiply bonded molecular fragments, phosphaalkynes undergo myriad reactions such as [1+2] cycloadditions, [3+2] cycloadditions, and [4+2] cycloadditions. This reactivity is summarized in graphical format below, which includes some examples of 1,2-addition reactivity (which is not a form of cycloaddition).