C-phosphorylation of n-methylpyrrole

Abstract

The phosphorylation of N‐methylpyrrole with phosphorus (III) halides has been studied. Migration of the dibromophosphino group from the second to the third position of N‐methylpyrrole, leading to the 3‐dibromophosphine, has been found. Methods for the synthesis of 2,4‐bisphosphorylated pyrroles have been developed. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10:213–221, 1999

1,2,5-Trimethylpyrrolyl Phosphines: A Class of Strongly Donating Arylphosphines

“…Zipse and co-workers studied substituents effects on the methyl cation affinity (MCA) of phosphines and showed that small N -heterocyclic substituents such as the pyrrolyl group lead to phosphines with remarkably high affinity to carbon electrophiles. , In the series of pyrrolylphosphines, the most effective electron-donating effects were observed when the phosphorus atom is connected to the C3 position of the pyrrole ring, while C2-connected pyrrolyl and phenyl substituents are comparable in this respect (Figure ). Tris­( N -pyrrolyl)­phosphine , is a weak electron donor and good π-acceptor ligand, which has been successfully applied in hydroformylation reactions. − The C2-connected structural isomer, tris­(1-methylpyrrol-2-yl)­phosphine, was first reported in 1974, followed by several derivatives of (1-methylpyrrol-2-yl)­phosphines. − Yet, the properties of these phosphines have barely been investigated. , Among them, the cataCXium ligands represent a prominent class of N -arylated pyrrolylphosphines, which have been used in Suzuki cross-coupling reactions . Few reports exist about C3-bound pyrrolylphosphines. ,,− In fact, the only representative with three pyrrolyl groups, tris­(1- tert -butylpyrrol-3-yl)­phosphine, has been generated in situ but was not isolated, and the electronic properties were not investigated .…”

“…Tris­( N -pyrrolyl)­phosphine , is a weak electron donor and good π-acceptor ligand, which has been successfully applied in hydroformylation reactions. − The C2-connected structural isomer, tris­(1-methylpyrrol-2-yl)­phosphine, was first reported in 1974, followed by several derivatives of (1-methylpyrrol-2-yl)­phosphines. − Yet, the properties of these phosphines have barely been investigated. , Among them, the cataCXium ligands represent a prominent class of N -arylated pyrrolylphosphines, which have been used in Suzuki cross-coupling reactions . Few reports exist about C3-bound pyrrolylphosphines. ,,− In fact, the only representative with three pyrrolyl groups, tris­(1- tert -butylpyrrol-3-yl)­phosphine, has been generated in situ but was not isolated, and the electronic properties were not investigated . Note that the structurally related (indol-3-yl)­phosphines are powerful ligands for Pd-catalyzed cross-coupling reactions. ,− Herein, we report the synthesis and properties of a series of (1,2,5-trimethylpyrrolyl)­phosphines that, consistent with Zipse’s prediction, are strongly electron-donating arylphosphines.…”

Facile synthesis and nematicidal activity evaluation of thiophosphinyl amide [(Pz)2P(S)NHR] and thiophosphonyl diamide [(Pz)P(S)(NHR)2] (Pz = 1,3,5-trimethylpyrazole, R = biphenyl derivatives)

“…A C-5 methyl group should prevent migration of a phosphine group between C-2 and C-3, a process that has been widely observed for other pyrazole derivatives. 36,37 In addition, some analogues of 2-aminobiphenyl have been employed as pesticidal agents.…”

Synthesis of Bis(imidazole‐2‐thion‐4‐yl)phosphanes

“…1 of biologically active compounds such as antibacterial [1], anti-inflammatory [2,3], analgesic [3], antitumor [4,5], anticancer activities [6] etc., and in organic synthesis is well documented [7][8][9][10]. The synthetic access to various C-phosphorylated five-membered N-heterocycles via electrophilic phosphorylation with P(III) halides is known [10][11][12][13]. The coordination of phosphanes to metals and the spectroscopic properties of phosphorus are two important aspects of this chemistry [14].…”