Study on the new synthetic reactions using phosphonate compounds

Abstract

In the course of study, research was performed to obtain beta-amido phosphonates from the reaction of lithiated alkyl phosphonates and dialkyl cyanamides, the resulting products were N-phosphorylated amidines, which can be produced via C→N migration of phosphoryl group. Migration can occur even in -78℃ regardless of the bulkyness of starting material. The carbon anion generated after migration is highly nucleophilic and several examples were performed. 2-Methyl-3-phosphorylchromanone was prepared in one-pot procedure from the reaction with lithiated allylphosphonate and ethyl salicylate. Allyl-vinyl migration seemed to occur in the reaction and subsequent Michael addition gave the resulting product. But other allylic phosphonates did not show the cyclized products. Only α-salicylated crotyl phosphonate afforded the 2-ethyl-3-phosphorylchromanone via $K_2CO_3$/acetone reflux. Thio-derivatives of 2-alkyl-3-phosphorylchromanone were also produced from methyl thiosalicylate via same procedure. alpha- And gamma-selectivities of several lithiated allylic phosphonates with carbonyl electrophiles were also scrutinized. It was found that α-, and γ-acylation occurred according to the bulkiness of electrophiles and allyl-vinyl migration occurred only in allyl phosphonate. Other allylic phosphonates such as crotyl, prenyl, and cinnamylphosphonates did not show the migration. Reactions of the alkyl tellurols generated in situ from dialkyl ditelluride and alkynes bearing electron-stabilizing groups such as phosphonyl or sulfonyl group gave the beta-organyltelluro vinyl phosphonates or sulfones in high yields. But Te-Metal exchange reaction did not show the successful results. Direct sulfonylation in alpha-position of alkyl phosphonates occurred in the reactions of alkyl phosphonate and benzenesulfonyl fluoride in presence of excess base. Subsequent addition of aldehydes also performed in the reaction mixture and the corresponding vinyl sulfones were obtained via one-pot proc...