A New Synthesis of (PhPSe₂)₂ (Woollins Reagent) and Its Use in the Synthesis of Novel P–Se Heterocycles

Abstract

A new and improved method for the preparation of (PhPSe2)2 (Woollins reagent (WR), 1) is reported. Reaction of dichlorophenylphosphine with Na2Se, (prepared from the reaction of elemental selenium and sodium in liquid ammonia) gives WR with excellent purity, high yield and on a larger scale than was previously possible. Four novel phosphorus-selenium heterocycles, including a spirocyclic heterocycle exhibiting a four-membered P2SeC ring, were obtained from the reaction of WR with two reactive substrates (diphenylcyclopropenone and methyl phenylpropiolate). Useful selenocarbonyl and thiocarbonyl compounds were obtained from the reaction of both WR and Lawesson's reagent with diphenylcyclopropenone. All new compounds were characterised spectroscopically and three demonstrative X-ray structures are reported.

How Not to Discover a New Reagent. The Evolution and Chemistry of Woollins' Reagent

“…The reactions predominantly lead to five membered C 2 PSe 2 rings. 45,59 Refluxing WR with symmetrically disubstituted alkynes (RCC-CCR, R = Ph, Si(CH 3 ) 3 ) in 2:1 molar ratio in toluene gave two product both containing five-membered P(Se)Se 2 C 2 heterocycles either with one unreacted triple bond 'dangling' or bis-heterocycles with two fivemembered P(Se)Se 2 C 2 rings are connected through a C-C single bond. However, WR and t Bu-CC-CC-t Bu react differently to afford an unprecedented fourmembered P(Se)SeC 2 heterocycle with one unreacted triple bond together with a fused bis-heterocycle containing two five-membered P(Se)SeC 3 rings fused at the middle two carbons of the diyne to give a heteropentalene analogue of pentalene, [3.3. Cleavage of the four-membered P 2 Se 2 ring in WR by alkyl diols affords the bisdiselenophosphonic acids quantitatively, the latter can be converted into the corresponding ammonium salts by treatment with butyl amine, followed by addition of I 2 /KI to give eight-, nine-and ten-membered ring diselenides in good to excellent yield (70 -90%) (Scheme 18), examples of each of these rings were characterized crystallographically ( Figure 8).…”

“…Interestingly, whilst LR simply thionated the substrate WR gave the selenketone derivative together with an unusual spirobicyclic system containing two four membered rings (eqn 11, Figure 9). 45 Template for SYNLETT and SYNTHESIS © Thieme Stuttgart · New York 2014-04-21 page 13 of 16…”

Organophosphorus‐Selenium Heteroatom Derivatives from Selenation of Primary/Secondary Amines and Haloalkanes/Dihaloalkanes

“…[4][5][6][7][8][9][10] 2,4-Bis(phenyl)-1,3-diselenadiphosphethane-2,4-diselenide [{PhP(Se)(µ-Se)} 2 ] (Woollins' reagent, WR), a selenium counterpart of the wellknown Lawesson's reagent (LR), has been well developed as an efficient phosphorus-selenium containing building block or selenation reagent in organic synthetic chemistry in recent years. 11 The reactions of WR with various organic substrates exhibit a diverse spectrum ranging from simple oxygen-selenium exchange to the formation of complex phosphorus-selenium heterocycles as well as the formation of surprising phosphorus-selenium-free products. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] We recently have reported the synthesis of a series of ammonium phenylphosphonamidodiselenoates and phenylphosphonamidodiselenoic diamides from the reaction of WR with primary or secondary amines, 26 and the formation of a series of organo phosphorus-selenium heteroatom derivatives from the selenation of alkenyl or arynyl-diamines.…”

Ammonium Phenylphosphonamidodiselenoates and Phenylphosphonamidodi‐selenoic Diamides from the Selenation of Primary and Secondary Amines

“…[7] 2,4-Bis(phenyl)-1,3-diselenadiphosphethane-2,4-diselenide [{PhP(Se)(µ-Se)} 2 ] (Woollins' reagent, WR, a selenium counterpart of Lawesson's reagent) has proved to be an efficient selenation reagent in organic synthetic chemistry in part due to its relatively pleasant chemical properties and ready preparation. [8] Reactions of Woollins' reagent with organic substrates display a wide spectrum ranging from simple oxygen-selenium exchange to the formation of complex phosphorus-selenium heterocycles as well as surprising phosphorus-selenium-free products. [9][10][11][12][13][14][15][16][17] Herein, as part of our investigation into the reactivity of Woollins' reagent towards different organic substrates, we report the synthesis of a series of novel ammonium phenylphosphonamidodiselenoates and phenylphosphonamidodiselenoic diamides from the selenation of primary/secondary amines, the complex of Cd 2 L 4 (L = [Se 2 PPh(NCH(CH 3 ) 2 ] -) and three representative related single crystal X-ray structures.…”