An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

Abstract

The synthesis of phosphonate esters is a topic of interest for various fields, including the preparation of phosphonic acids to be employed as organic linkers for the construction of metal phosphonate materials. We report an alternative method that requires no solvent and involves a different order of addition of reactants to perform the transition-metal-catalyzed C–P cross-coupling reaction, often referred to as the Tavs reaction, employing NiCl2 as a pre-catalyst in the phosphonylation of aryl bromide substrates using triisopropyl phosphite. This new method was employed in the synthesis of three novel aryl diphosphonate esters which were subsequently transformed to phosphonic acids through silylation and hydrolysis.

Synthesis and bioactivity of psilocybin analogues containing a stable carbon–phosphorus bond

“…Michaelis-Arbuzov reaction was evaluated under mild reaction conditions using BF 3 •Et 2 O. After 4 h,31 P-NMR revealed the presence of triethyl phosphite, the product of its hydrolysis and its oxidation (triethyl phosphate). However, no evidence of product formation was observed.…”

“… 30 Reactions on 4-bromo indole and 5-bromo tryptamine in the ionic liquid failed to form the product, leaving only triethyl phosphite, diethyl phosphite and triethyl phosphate according to 31 P-NMR. Additionally, we evaluated a nickel-catalyzed Tavs reaction according to the procedure of Shearan et al 31 Again, no evidence of product formation was found after 54 h of stirring at 160 °C. Another option to introduce a phosphonate group is the Hirao coupling.…”

Organophosphorus chemistry: from model to application

“…Cross-coupling reactions are also of importance in organophosphorus chemistry. Taddei and co-workers applied an alternative method to the classical Hirao reaction [ 1 ]. They utilized the Ni-catalyzed double Michaelis–Arbuzov reaction of bis(bromoaryl) species and related N-heterocycles to prepare the respective bisphosphonate derivatives that were transformed to the corresponding diphosphonic acids.…”