Synthesis of Organophosphorus Compounds under Microwave Conditions

Synthesis of Cyclic Phosphinates by Microwave-Assisted Ionic-Liquid-Promoted Alcoholysis

“…[11][12][13][14] An elegant method is the microwave (MW)-assisted direct esterification of the phosphinic acid II with alcohols at a temperature ≥180 °C ('C'). [15][16][17] Later on, it became clear that a suitable ionic liquid (IL) additive may catalyze the MW-promoted esterification. 18,19 An alternative possibility is the T3P ® -promoted esterification ('D').…”

“…20,21 Last but not least, the cyclic esters IV may also be obtained by alkylating es-terification, by the reaction of phosphinic acid II with alkyl halides in the presence of K 2 CO 3 under solvent-free MW conditions ('E'). 16,22 Cyclic phosphinates were synthesized by olefin metathesis, 23 and representatives with 5-membered rings were found to have biochemical importance. 24 Scheme 1 Possibilities for the preparation of 1-alkoxy-3-phospholene 1-oxides IV If C 1 or C 2 alkyl esters of certain substrates are available, alcoholysis (transesterification) is a good method to convert them into esters with longer alkyl chains.…”