Organolithium reagents, reaction with sulfones

Whereas the reactions of sulfones with nucleophiles via pathways A and B of equation 1 are most frequently observed, the nucleophilic substitution reaction by pathway D has been observed only in the cases where the leaving carbanion can be stabilized, or in the highly strained molecules. Chou and Chang3 has found recently that an organolithium reagent attacks the sulfur atom of the strained four-membered sulfone in 34. When this sulfone is treated with 1 equivalent methyllithium, followed by workup with water or Mel, 38 or 39 are formed in high yield. 

The reacuons of electrophihc tnflyl sources with nucleophiles were investi gated The reaction of tnfhc anhydride with an organolithium reagent is not synthetically promising because of ditnflylation and other side reactions [20] When phenyllithium reacts with tnfhc anhydnde, dimerization products and acetylenic Michael diadducts are observed [20] (equation 17), but using the sodium salt of the alkynes instead of the lithium salt provides the alkynyl tnfluoromethyl sulfones [21] (equation 18) (Table 7) Alkynyl tnfluoromethyl sulfones are of synthetic interest, because they show a pronounced reactivity toward nucleophiles in addition reactions and cyclopentadiene in Diels-Alder reactions [21] (Table 7)... 

A(-(Arylthiomethyl)amines, which are easily prepared and reportedly have better shelf stability than the corresponding )V-(alkoxymethyl)amines, have also been utilized to prepare tertiary amines. Alkenyl cuprate addition to )V,A -diethylphenylthiomethylamine produces allylic amines in high yield (entry 1, Table 6). Both alkenyl groups of the cuprate react. 5-(Dialkylaminomethyl) dithiocarbamates (entry 2, Table 6), sulfonates (entry 3, Table 6) and amides also generate iminium salts in situ. Of a variety of amides examined, imides such as dialkylaminomethyl-succinimides (entry 4, Table 6) and -phthali-mides provide the best overall yields. Organolithium reagents are rarely utilized in aminomethylation reactions. However, )V-chloromethylamines condense readily with lithiated anisole derivatives (entry S, Table 6). ... 

The organolithium reagent (1) also reacts with a wide variety of other electrophiles, including silyl chlorides to provide bis(silyl)methane derivatives, and nitriles to provide -sUyl amines after in situ reduction of the intermediate imine derivative. a-Silyl epoxides are opened to provide the substituted vinylsilane. Reaction of (1) with arenesulfonyl fluorides provides a-silyl sulfones, key intermediates for the preparation of vinyl sulfones. Reaction of the lithium reagent (1) with alu-... 

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