dimetyloallylofosforan

dimetyloallylofosforan is an organophosphorus compound formally known as dimethyl‑allylphosphonate. Its IUPAC name is dimethyl (3-methylbut-2-en-1-yl)phosphonate and its molecular formula is C7H14O4P. The compound appears as a pale yellow or colorless liquid with a faint fruity odor. It has a reported melting point of –30 °C and boils at approximately 190 °C under reduced pressure. The molecular weight is 170.16 g mol‑1. The structure consists of a phosphonate core (P=O) bound to two methoxy groups and a dimethylallyl side chain (3-methylbut-2-en-1-yl).

In synthetic chemistry dimetyloallylofosforan is employed as a phosphorylating reagent for the preparation of phosphoramidates, phosphorothioates and related anhydrides. It serves as a mild, selective electrophile and can be used to achieve regioselective protection of alcohols in complex molecule synthesis. The compound can be prepared by the phosphorylation of dimethylallyl alcohol with chlorophosphinic acid followed by methanolysis, or via the reaction of dimethylallyl bromide with triethyl phosphite, followed by hydrolysis.

Hazards arise from its phosphorous content and ability to undergo hydrolysis to release methyl alcohols and dimethylallyl alcohol, both irritants. The substance is considered toxic by oral, dermal and inhalation routes, with acute LD50 values reported around 400 mg kg‑1 in rodents. Exposure can lead to irritation of the eyes, skin and respiratory tract. Standard protective equipment and handling in a fume hood are recommended. Regulation of dimetyloallylofosforan varies by jurisdiction; in many regions it is listed as a controlled precursor for the synthesis of certain organophosphate nerve agents. Safe disposal requires hydrolysis to non‑phosphorylated derivatives before waste management.