Synthesis and Some Reactions of (Triphenylphosphonio) methyl Dithiocarbamate Bromide

Abstract

A new phosphonium salt, (triphenylphosphonio)methyl 1-pyrrolidinecarbodithioate bromide [7], was prepared from the reaction of (bromomethyl)triphenylphosphoniurn bromi[de and pyrrolidinium 1-pyrrolidinecarbodithioate in 85% yield.
Treatment of the salt [7] with potassium t -butoxide at 0°C in tetrahydrofuran gave a yellow solution of the ylide [8], which reacted with various aldehydes and activated ketones, such as biacetyl, benzil, and methyl pyruvate, to give the corresponding vinyl esters [9] in moderate to high yields (Table 1).
It was found that the ylide [8] is rather stable than the ylides [10] and [11], which were generated from (triphenylphosphonfo)methyl arenecarbothioate bromides [5] and carbodithioate iodides [ 6 ].
The reaction of [9] with some nucleophiles was investigated (Table 2). The esters [9] were converted to the corresponding vinyl sulfides [4] via the alkenethiolates [3]by treatment with n-BuLi, followed by alkylating agent.