Microwaves as “Co-Catalysts” or as Substitute for Catalysts in Organophosphorus Chemistry

Abstract

The purpose of this review is to summarize the importance of microwave (MW) irradiation as a kind of catalyst in organophosphorus chemistry. Slow or reluctant reactions, such as the Diels-Alder cycloaddition or an inverse-Wittig type reaction, may be performed efficiently under MW irradiation. The direct esterification of phosphinic and phosphonic acids, which is practically impossible on conventional heating, may be realized under MW conditions. Ionic liquid additives may promote further esterifications. The opposite reaction, the hydrolysis of P-esters, has also relevance among the MW-assisted transformations. A typical case is when the catalysts are substituted by MWs, which is exemplified by the reduction of phosphine oxides, and by the Kabachnik–Fields condensation affording α-aminophosphonic derivatives. Finally, the Hirao P–C coupling reaction may serve as an example, when the catalyst may be simplified under MW conditions. All of the examples discussed fulfill the expectations of green chemistry.

Green and Effective Preparation of α-Hydroxyphosphonates by Ecocatalysis

“…However, they are often used in stochiometric amounts; the reactions are substrate specific and, most importantly for green chemistry considerations, the production of the salts is far from environmentally friendly, with harsh production processes, poor impact assessment, and positive carbon footprint. Additionally, examples of the use of specific techniques such as microwave irradiation [ 49 ] and biocatalysis [ 50 ] as green methodologies leading to hydroxyphosphonates are also described in the literature. However, the use of microwave irradiation is exclusively limited to the use of few substituted aromatic aldehydes, and no examples for the use of aliphatic or heteroaromatic aldehydes, or ketones were reported [ 49 ].…”

“…Additionally, examples of the use of specific techniques such as microwave irradiation [ 49 ] and biocatalysis [ 50 ] as green methodologies leading to hydroxyphosphonates are also described in the literature. However, the use of microwave irradiation is exclusively limited to the use of few substituted aromatic aldehydes, and no examples for the use of aliphatic or heteroaromatic aldehydes, or ketones were reported [ 49 ]. Biocatalytic methods [ 50 ] can be applied to a wider range of aldehydes, albeit the yields of final products are low (11–40% and 68% yield in the best case) and additionally isolation of pure products requires tedious chromatographic purification.…”

Synthetic Methods for Azaheterocyclic Phosphonates and Their Biological Activity: An Update 2004–2024

“…Several methods capable of the formation of a C–P bond have been discovered and explored in depth over the years, mainly in attempts to make them more sustainable, such as the Michaelis–Arbuzov reaction, Michaelis–Becker reaction, Pudovik reaction, Hirao coupling, Kabachnik–Fields reaction, and more . Because of their widespread use in organic chemistry, these methods themselves have been subject to numerous reviews. − Some connection between this work and past reviews on related topics is possible because several of the cyclic and aromatic derivatives also fit our scope.…”

Deamination of 1-Aminoalkylphosphonic Acids: Reaction Intermediates and Selectivity

“…In that regard, the use of 1-aminoalkylphosphonic acids in drug discovery has proven successful in many cases, with prominent examples being potential drugs for the treatment of diabetes [10,11], asthma [12], inflammation [13], heart failure [14], cancer [15], malaria [16], and HIV [17]. Due to the importance of the 1-aminoalkylphosphonic acids, several synthetic methods for their preparation have been designed over the years [18][19][20][21][22][23][24][25][26].…”