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You are using Science Of Synthesis as a Guest. Please login or sign up for a free trial to access the full content. Method 1: Hydrophosphinylation of Alkynes

DOI: 10.1055/sos-SD-033-00773

Gaumont, A. C.; Gulea, M.Science of Synthesis, (200733695.

Unsaturated CC bonds undergo hydrophosphinylation under metal-[‌2‌] or radical-catalyzed conditions.[‌1‌] The palladium-catalyzed hydrophosphinylation of alkynes represents an efficient and general method for preparing alk-1-enylphosphinates.[‌3‌‌5‌] The reaction between phosphinates and terminal alkynes gives the branched alk-1-enylphosphinates 1 exclusively if dichlorobis(triphenylphosphine)palladium(II)/methyllithium is used as the catalyst. However, the linear adduct 2 is the major product if the tris(benzylideneacetone)dipalladium/9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (Xantphos) couple is used as the catalyst (Scheme 1).[‌5‌] Similarly, the addition of aqueous phosphinic acid 3 to dibutylacetylene also occurs under these conditions, leading directly to the alkenylphosphinic acid 4 (Scheme 1).[‌5‌] Furthermore, a new nickel-catalyzed hydrophosphinylation has been developed, which is useful for the preparation of phosphinate esters. The process involves the addition of alkyl phosphinates to alkynes, in the presence of a catalytic quantity of nickel chloride (23mol%) in refluxing acetonitrile, without a ligand.[‌6‌]

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