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A series of tertiary phosphine sulfides and selenides have been synthesized in excellent yields (88‐99%) via a three‐component reaction between secondary phosphines, electron‐rich alkenes (styrene, vinyl chalcogenides), and elemental sulfur or selenium, proceeding under solvent‐free conditions (80‐82°C, 4–44 h). The interaction occurs via initial oxidation of secondary phosphines with elemental sulfur or selenium followed by noncatalyzed anti‐Markovnikov addition of the generated R2P(E)H (E = S, Se) species to alkenes to afford the corresponding adducts with high chemo‐ and regioselectivity.

The first examples of a facile hydrochalcogenophosphorylation of alkyl vinyl selenides are reported. The regiospecific addition of secondary phosphine sulfides and phosphine selenides to vinyl selenides proceeds under radical initiation (AIBN, 65-70°C, 1 h or UV-irradiation, 1 h) to afford the anti-Markovnikov adducts in 87-95% yield.Tertiary phosphine chalcogenides are important ligands in the design of new metal-complex catalysts 1 (in some catalytic processes they show even better results than the corresponding tertiary phosphines 1a ), building blocks in the synthesis of biologically active compounds (for example, anti-arthritic gold complexes 2 ) and intermediates for semi-conducting nanomaterials. 3 In recent years there has been increasing interest in functional phosphine chalcogenides as polydentate 'hemilabile' ligands 4 such as R 2 P(X)CH 2 CH 2 SR¢ (X = O, S), which has been used, for example, in myocardial imaging. 4c,d The substitution of an alkyl sulfide fragment for an alkyl selenide group in these compounds expands the scope of practical applications of tertiary phosphine chalcogenides. Meanwhile, to the best of our knowledge, such functional tertiary phosphine sulfides and phosphine selenides with alkyl selenide moieties have not been reported in the literature.The goal of the present work was to study the reaction of available secondary phosphine chalcogenides 5 with alkyl vinyl selenides, which were easily prepared from elemental selenium, acetylene and alkyl halides, 6 in order to develop a general, expedient and atom-economic method for the synthesis of functional tertiary phosphine chalcogenides containing alkyl selenide fragments.We have found that secondary phosphine sulfides 1, 2 and selenides 3, 4 add regiospecifically to alkyl vinyl selenides 5, 6 under mild conditions (AIBN, 65-70°C or UV-irradiation, dioxane, 1 h) to give tertiary alkylselanylphosphine chalcogenides 7a-h in 87-95% yield (Table 1).Secondary phosphine oxides showed less reactivity in this reaction. Thus, heating (65-70°C, 20 h, dioxane) diphenylphosphine oxide with vinyl selenide 5 in the presence of AIBN gave 2-(hexylselanyl)ethyl(diphenyl)phosphine oxide (8) in ~40% yield ( 31 P NMR). Another product of the reaction, diphenylphosphinic acid (~60% yield; d p = 28.94 ppm), is likely to result from the oxidation of diphenylphosphine oxide by air.At the same time, the phosphine oxide 8 was prepared in high isolated yield by the oxidation of alkylselanylphosphine selenide 7g with aqueous hydrogen peroxide (r.t., 10 min, acetone) as shown in Scheme 1. Scheme 1In summary, work described here on the addition of secondary phosphine chalcogenides to vinyl selenides contributes to the understanding of the reactivity of these compounds, provides a facile synthesis of new tertiary phosphine chalcogenides with alkyl selenide substituents and extends the synthetic potential of reactions of PH-addends with alkenes. Such reactions represent one of the most convenient approaches to C-P bond formation and continues to attract attention ...

Thiophene and its substituted derivatives (particularly diphenylthiophenes) find a wide practical use and they continue to attract the attention of investigators as building blocks for organic synthesis [1][2][3]. One of the routes to the synthesis of diphenylthiophenes is the reaction of elemental sulfur with styrene. Unfortunately this is unselective and heating elemental sulfur with styrene (140-230°C) forms a complex mixture of acyclic and cyclic (2,4-diphenylthiophene, 2,4-diphenylthiophane, 2,5-diphenyl-1,4-dithiane, 2,5-diphenyl-2,3-dehydrothiane) products among which rubber like polysulfide oligomers and polymers predominate [4][5][6]. Increasing the selectivity of the synthesis of diphenylthiophenes from styrene and elemental sulfur remains an unresolved problem.We have found that styrene reacts with elemental sulfur in the strongly basic medium KOH-DMSO [7] in the presence of hydroquinone under microwave irradiation (600 watts, 4 min) to form a 1: 12 mixture of 2,4-and 2,5-diphenylthiophenes 1a,b in overall 30% yield (not optimized). Ph S Ph Ph S Ph PhThe diphenylthiophenes are not formed when the elemental sulfur and styrene are heated (85-90°C, 6 h) in the system KOH-DMSO-hydroquinone in the absence of the microwave irradiation and the unreacted styrene is recovered.In the absence of the hydroquinone the reaction is less selective. Along with the thiophenes 1a,b GC-MS analysis of the reaction mixture shows the presence of bis(2-phenylethyl) sulfide, bis(2-phenylethyl) disulfide, 1,4-diphenylbuta-1,3-diene, and 1,3,5-triphenylbenzene. _______ * Dedicated to Academician M. G. Voronkov, Russian Academy of Sciences in his 85 th year. __________________________________________________________________________________________ A. E.

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