Replacement of C−O by P−O in Cyclic Acetals and Ketals

Efficiency and structural specificity earmark the reaction of phosphonium ions 1 with cyclic acetals and ketals to yield 1,3,2‐dioxaphospholanium ions 2 Eq. (1)]. Potential applications of this reaction are in monitoring trace levels of organophosphorus esters and in developing novel carbonyl deprotection agents. R=OCH₃, CH₃; R¹=H, CH₃; R²=CH₃, C₆H₅; R³=H, CH₃.