Substituted ethynylphosphonates and their anticholinesterase activity

Dialkyl 1-Alkynylphosphonates: a Range of Promising Reagents

“…These compounds were readily obtained from dialkyl or diphenyl chlorophosphates and the appropriate terminal alkynylmagnesium bromide, which was in turn prepared from the alkyne 21 and ethylmagnesium bromide in Et 2 O or THF (Scheme 9). [56] The most widely employed phosphorus reagent is diethyl chlorophosphate 19 (R ϭ Et), which is reacted with the alkynylmagnesium bromide through direct [33,34,57] or inverse [56] addition at 0°C in Et 2 O or at Ϫ30°C in THF. This procedure has successfully been employed for the preparation of a variety of dialkyl 1-alkynylphosphonates 3 in fair to good yields (51 to 76%), with the best results generally obtained by addition of the alkyne salt to the chlorophosphate.…”