An Azophosphine Synthetic Equivalent of Mesitylphosphaazide and Its 1,3-Dipolar Cycloaddition Reactions

Abstract

Dibenzo-7-phosphanorbornadiene-substituted diazene MesN 2 PA (1, where Mes = mesityl, A = anthracene, or C 14 H 10 ), a synthetic equivalent of mesitylphosphaazide (MesN 2 P) and anthracene, was synthesized by treatment of [Ph 3 BPA][Na(OEt 2 ) 2 ] with [MesN 2 ]OTf (OTf = CF 3 SO 3 − ) in thawing tetrahydrofuran (14% isolated yield). Treatment of 1 with unsaturated molecules cyclooctyne, [Na(dioxane) 2.5 ][OCP] (phosphaethynolate), and Ad−CP (Ad = adamantyl) results in the corresponding [3 + 2] phosphaazide-(phospha)alkyne cycloadducts, with concomitant loss of anthracene in 65%, 49%, and 38% isolated yield, respectively. Structural data for the phosphaethynolate cycloadduct ) 2 ]) were obtained in a single-crystal X-ray diffraction study. A diazatriphosphole was generated by combining 1 with P 2 A 2 , a thermally activated anthracenebased molecular precursor to diphosphorus (P 2 ). Thermolysis (33−65 °C) of 1 in benzene-d 6 leads to anthracene extrusion. This process has a unimolecular kinetic profile and proceeds with activation parameters of ΔH ⧧ = 21.6 ± 0.3 kcal/mol and ΔS ⧧ = −4.9 ± 0.8 cal/(mol K).

DFT study of regio- and stereo-selective 13DC reaction between diazopropane and substituted chalcone derivatives: Molecular docking of novel pyrazole derivatives as Anti-Alzheimer’s Agents

“…A number of theoretical and experimental studies (Kalita et al, 2021;Riu et al, 2021) have shed light on the mechanism of reaction of Huisgen chemistry. Most of the experimental of 1,3dipolar cycloadditions, which based largely of a diazoalkane to functional alkynes (Hamdi et al, 2005), with several cyclobutenes (Burdisso et al, 1990), with imidates (Hamdi and Dixneuf, 2007), propargyl alcohols (Hamdi et al, 2005) … Since 2003 (Hamdi et al, 2003), we showed a simple method for the 1,3-dipolar cycloadditions based on the reaction the 2-diazopropane (DAP) DE with enones (chalcone derivatives) DP.…”

Introducing N-Heterocyclic Iminophosphoranes (NHIPs): Synthesis by [3 + 2] Cycloaddition of Azophosphines with Alkynes and Reactivity Studies

“…In this context, cyclic iminophosphoranes ( 1 and 2 in Scheme C), having geminal aromatic substitutions α to the basic nitrogen, were prepared by 1,3-dipolar cycloaddition of phosphinoimine (Ph 2 CN–PR 2 ) and dimethylacetylene dicarboxylate (DMAD). − The resulting cyclic iminophosphorane 1 was used as a ligand for gold­(I), but further reactivity studies have not been pursued presumably because of the extreme steric crowding at the basic nitrogen atom. Recently, the cycloaddition of MesNNP A ( A = anthracene) and cyclooctyne was disclosed, where a nucleophilic phosphorus center and an electrophilic NN π* component enabled MesNNP A to react as a 1,3-dipole (Scheme A) . This result motivated us to investigate the cycloaddition reaction of alkynes and azophosphines, which do not have an anthracene leaving group (Scheme B).…”

“…Recently, the cycloaddition of MesNNPA (A = anthracene) and cyclooctyne was disclosed, where a nucleophilic phosphorus center and an electrophilic N�N π* component enabled MesNNPA to react as a 1,3-dipole (Scheme 1A). 20 This result motivated us to investigate the cycloaddition reaction of alkynes and azophosphines, which do not have an anthracene leaving group (Scheme 1B). This cycloaddition reaction provides a new class of heterocycles, Nheterocyclic iminophosphoranes (NHIPs), which are structur-ally similar to cyclic (alkyl)(amino)carbenes (CAACs; Scheme 1C).…”

Staudinger Reactivity and Click Chemistry of Anthracene (A)-Based Azidophosphine N3PA

“…Inspired by Carpino’s hydrazine, the Cummins group developed in the past decade the synthesis of dibenzo-7λ 3 -phosphanorbornadiene derivatives, which serve as molecular precursors for the release of reactive phosphorus species. − In an initial study, Velian and Cummins demonstrated the direct reaction of Mg A ·3THF ( A = C 14 H 10 or anthracene; THF = tetrahydrofuran) with phosphorus dichlorides, RPCl 2 [R = tert -butyl ( t Bu), 2,3:5,6-dibenzo-7-azabicyclo[2.2.1]­hepta-2,5-diene (dbabh), (Me 3 Si) 2 N (HMDS), i Pr 2 N], to afford 7λ 3 -phosphanorbornadiene (RP A ) derivatives . These RP A compounds served as starting materials for the synthesis of further A -based molecular precursors for the mild release of small phosphorus-bearing species, including diphosphorus (P 2 ) and HCP. − …”