Darstellung höherer Alkylester von Phosphor‐, Phosphon‐ und Phosphinsäuren durch Umalkylierung

Abstract

In Gegenwart tertiärer Phosphine reagieren höhere Alkylhalogenide bei 140–180°C mit Methyl‐ oder Äthylestern von Phosphor‐, Phosphon‐ und Phosphinsäuren (I) leicht unter Freisetzung von Methyl‐ oder Äthylhalogeniden. Dabei entstehen im Sinne einer schrittweisen Umalkylierung die höheren Alkylester der Phosphor‐Säuren. Die katalytische Wirkung der tertiären Phosphine beruht auf der primären Bildung quartärer Phosphoniumhalogenide, die sich chne Beeinträchtigung der Esterausbeute auch durch Lithiumchlorid ersetzen lassen.

The acid-catalyzed hydrolysis of phosphinates. III. The mechanism of hydrolysis of methyl and benzyl dialkylphosphinates

“…Benzyl diethylphosphinate has been synthesized by a method different from that reported here but the compound was not characterized (24). For all compounds nmr and infrared spectra were consistent with structural assignments.…”

“…The slopes of the ester had partially decomposed into acid and alcohol. the plots were obtained by a least squares computer Henning et al (24) have prepared the benzyl ester by a analysis. The rate constant, kobs, is then equal to 2,303 transalkylation reaction of ethyl diethylphosphinate and (slope)/3600 s-l. benzyl chloride using a catalytic amount of triphenylphosphine.…”

Sugar lactams. III. Synthesis of five-,six-, and seven-membered analogs

“…As in the reductive ring enlargement of appropriately substituted 5-azido-5-deoxypentoses,6 the product 3 contains an unsubstituted hydroxyl group at C-4 which originates from the ring oxygen by protonation and can be used advantageously for further selective transformations at that site. Benzoylation of 3 at elevated temperatures caused substitution at the hydroxyl and NH groups to give the crystalline dibenzoate 4. Attempted removal of the acetal group from 3 in the presence of Amberlite IR-120 (H+) afforded a negligible residue when the filtered solution was evaporated to dryness.…”