Dual Radical/Polar Pudovik Reaction:  Application Field of New Activation Methods

Abstract

The Pudovik reaction (addition of organophosphorus compounds containing a labile P-H bond with alkenes and alkynes) can progess via a radical or (and) ionic mechanism. A comparative and systematic study including various reagents and different activation methods (heating, photochemical or ultrasonic irradiation, and dry medium supported reactions) is presented. Photolysis is the most efficient method for the radical processes, but in a few examples, ultrasonic irradiation can be more appropriate since the reaction time is shorter and ultrasound did not induce side-reactions (in particular Z/E isomerization). Dry medium process on basic solid support is the best anionic activation (yield, time, selectivity, purification facilities). Ultrasound, by its mechanical effects, can contribute to increase yield compared to the classical thermal method under these basic conditions. All the activation methods are efficient whatever the unsaturated substrates for the phosphine reactivity, whereas the appropriate activation method is exclusively determined by the nature of the unsaturated system for the thiophosphine (or phosphine oxide) reactivity.

Facile Synthesis of Hyper‐Branched Tetraphosphanes and Tetraphosphane Chalcogenides

“…This is in agreement with literature data that lower activity of secondary phosphane oxides in radical additions is often observed. [26] To check the reactivity of the phosphane centers in the hyper-branched surroundings of the adducts we used tetraphosphanes 8 and 9 in typical phosphane reactions. It was found that tetraphosphanes 8 and 9 were smoothly oxidized by air (room temp., 40 h, acetone) or elemental sulfur and selenium (50°C, 1 h, toluene) to quantitatively give the corresponding tetraphoshane chalcogenides 10-14 (Scheme 2).…”

Radical addition reaction of bis(naphth‐1,8‐diyl‐8‐oxy)hydrophosphorane to olefins

“…The mixture was quenched with 6 M HCl (400 mL) and extracted with 2:1 THF/Et 2 O (300 mL × 5). The collected organic layer was dried over MgSO 4 …”

“…c 2011 Wiley Periodicals, Inc. approaches to organophosphorus compounds, the formal addition reaction of a P H bond to an unsaturated C C bond, catalyzed by transition metal compounds [1,2] or induced by radical initiators [3,4], has attracted much attention because most of the reactions are convenient and regioselective. Although numerous radical addition reactions of trior tetracoordinate phosphorus compounds bearing P H bond to various olefins have been reported, only a few examples of the radical addition reactions of pentacoordinate hydrophosphoranes to terminal olefins are known [5].…”

Phosphorus‐Containing Epoxy Curing Agents via Imine Linkage

“…Scheme 2 shows the proposed conjugate-addition mechanism [21] for the synthesis of (3)-(4). The minimum energy Phosphorus-Containing Epoxy Curing Agents via Imine Linkage models of (1() and (2(), the carbocation intermediate do not exhibit planar structures, so the DOPO anion will not attack equally from the top or bottom faces.…”