[38066-16-9] · C11H17O3PS · Diethyl Phenylthiomethylphosphonate · (MW 260.29)
(used for the conversion of aldehydes and ketones to vinyl sulfides, which can be hydrolyzed to yield homologated aldehydes and ketones)
Physical Data: bp 145-150 °C/0.5 mmHg.1
Solubility: sol CH2Cl2, THF, MeOH.
Form Supplied in: neat liquid.
Preparative Methods: although the reagent is commercially available, there are a number of methods available for its preparation.
A useful alternative to the Arbuzov reaction is the Michaelis-Becker reaction between phenylthiomethyl chloride and sodium diethyl phosphite (eq 2).3
An umpolung version of the Michaelis-Becker reaction involves the treatment of Diethyl Phosphorochloridate with lithiated methyl phenyl sulfide (eq 3).1
Moderate yields have been obtained in the Mitsunobu coupling of diethyl 1-hydroxyalkylphosphonates and thiophenol (eq 4).4
Handling, Storage, and Precautions: has a stench and is an irritant, but is reasonably stable for storage. Reactions involving this reagent are best conducted under anhydrous conditions, under nitrogen, in a well ventilated fume hood.
In general, anions generated from diethyl phenylthiomethylphosphonate can be alkylated or reacted with aldehydes or ketones to make vinyl sulfides or vinylphosphonates. We shall consider only selected examples here because most of the reactions of diethyl phenylthiomethylphosphonate are strictly analogous to those of Diethyl Methylthiomethylphosphonate and the reader is referred to that entry.
The reaction of metalated diethyl phenylthiomethylphosphonate with ketones to give vinyl sulfides often proceeds in excellent yields (eq 5).5
The reaction of lithiated diethyl phenylthiomethylphosphonate with aryl nitriles to give ketimines, followed by hydrolysis, provides a simple route to synthetically useful b-keto sulfides (eq 6).6 Alternatively, the anion can be quenched with Carbon Dioxide to furnish a-phenylthiodiethylphosphonocarboxylic acids (eq 6).7
Reaction of the lithiated reagent with alkyl halides, followed by oxidation to a sulfoxide and elimination, constitutes an efficient synthesis of predominately trans-vinylphosphonates (eq 7).8
Treatment of the reagent with N-Chlorosuccinimide gives diethyl a-chlorophenylthiomethylphosphonate,3,9 which can be reacted with alcohols to furnish O,S-acetals or metalated and reacted with aldehydes and ketones in the usual way to furnish 1-chloro-1-phenylthioalkenes (eq 8).9 Initial oxidation to the sulfone followed by metalation and condensation with aromatic aldehydes furnishes 1-chloro-1-phenylsulfonylalkenes (eq 8).10
Controlled oxidation of the reagent to give Diethyl Phenylsulfinylmethylphosphonate is discussed separately under the section for that reagent.
K. Shankaran & Sherman T. Waddell
Merck Research Laboratories, Rahway, NJ, USA