Synthesis and structure of sulphur derivatives of a methylenephosphine

(σ3,λ5)‐phosphoranes versus (σ3,λ3)‐thiaphosphiranes: Quantum chemical investigation of products of phosphaalkene sulfurization

“…A sulfurization of phosphaalkenes a yields either (σ 3 ,λ 5 )‐phosphoranes b [1–12] or (σ 3 ,λ 3 )‐thiaphosphiranes c [13–16] as reaction products. The first class (b) arises as a result of formation of a double bond between the sulfur and phosphorus atoms, whereas c can be formally considered as a product of sulfur addition to the double phosphorus–carbon bond in phosphaalkenes.…”

“…The role of electronic and steric factors in controlling the mentioned reaction pathways still remains unclear. Among the published products of sulfurization of phosphaalkenes, in most cases (σ 3 ,λ 5 )‐phosphoranes were isolated[1–12] and only in four cases (σ 3 ,λ 3 )‐thiaphosphiranes were formed. [13–16] It might be suggested that bulky substituents (for instance, Mes* (2,4,6‐tris(tert‐butyl)phenyl), Mes, fluorenylidene) attached to the phosphorus atom or carbon atom promote the formation of phosphoranes as products of the sulfurization reaction.…”

“…In addition, phosphoranes b were formed by thermodynamically controlled (σ 4 ,λ 5 )‐thioxothiaphosphiranes desulfurization, whereas under conditions of kinetic control thiaphosphiranes c were preferable. [3, 9–11, 17] Thus, there are every reasons to suggest that sulfurization of phosphaalkenes, even sterically crowded ones, is a thermodynamically driven process. An interconversion between b and c is controlled by orbital symmetry and hence is a thermally allowed reaction.…”

“… Products of sulfurization of phosphaalkenes (experimental results). 1b–9b : 1 [1] X = N(SiMe 3 ) 2 , Y 1 = SiMe 3 , Y 2 = H; 2 [7] X = N(SiMe 3 ) 2 , Y 1 = SiMe 3 , Y 2 = trans‐CHCHSiMe 3 ; 3 [2] X = 2,6‐dimethyl‐C 6 H 3 ; Y 1 = Y 2 = Ph; 4 [3, 4] X = Mes, Y 1 = Y 2 = SiMe 3 ; 5 [6] X = Mes*, Y 1 = H, Y 2 = Ph; 6 [9, 10] X = Mes*, Y 1 = Y 2 = Ph; 7 [5] X = Mes*, Y 1 = Y 2 = SiMe 3 ; 8 [11] X = Mes*, Y 1 +Y 2 = flyorenylidene; 9 [11] X = Mes*, Y 1 +Y 2 = dibenzo[a,d]cycloheptatrienylidene. 10c–13c : 10 [14] X = t‐Bu, Y 1 = t‐Bu, Y 2 = H; 11 [13] X = CCSiMe 3 , Y 1 = Y 2 = SiMe 3 ; 12 [16] X = NEt 2 , Y 1 = H, Y 2 = P(NEt 2 ) 2 C(CN)CH(CF 3 ) 2 ; 13 [15] 9a‐tert‐butyl‐3,9‐diphenyl‐9,9a‐dihydro‐3,9‐epoxy[2]benzophosphepino[2,3‐b]thiaphosphiren‐8(3H)‐one.…”

Persulfuration of phosphinines: Synthesis and X‐ray crystal structure analysis of a P2S3 derivative

“…Since our initial report, phosphinine 1 -sulfides have been generated by thermal decomposition of 1 -phospha-2-thiabicyclo[4. 4 .O]deca-3,7,9-triene 1 -sulfides [2] and a stable example has been reported [3]. In view of the aromaticity loss that accompanies the sulfuration of phosphorus, it seemed to us that the reaction of phosphinines with sulfur deserved more attention.…”