Cyanide, reaction with sulfonate esters

As with cyanide, Sn2 reactions of alkyne anions can be done with substrates other than halides or sulfonate esters. Epoxides are opened by acetylides at the less sterically hindered carbon to give an alkynyl alcohol. A synthetic example is the reaction of epoxide 38 with the indicated lithium alkyne anion gave an 85% yield of 39, an intermediate in the Sinha et al. synthesis of squamotacin.49... 

Reaction of a cyanide ion with an alkyl halide or a sulfonate ester (9.2,11.3). 

Propargylic Anion Equivalent. (TMS)allene reacts with electrophiles at the C-3 position in an Se2 process analogous to electrophilic substitution reactions of allyl- andpropargylsilanes. For example, upon treatment with trimethylsilyl chlorosulfonate or sulfur trioxide-1,4-dioxane, (TMS)allene yields silyl esters of sulfonic acids (eq 3). (TMS)allene undergoes conjugate addition with a, 8-unsaturated acyl cyanides to yield 5,e-acetylenic acyl cyanides. ... 

These reactions are carried out in aqueous/organic two-phase solvent systems with one of the reagents in an alkali metal salt form. Some examples of the anionic nucleophilic reagents (Y) are hydroxides, halides, cyanides, sulfides, cyanamides, carboxylates, sulfonates, and so forth. In fact, one of the most studied PEG phase transfer catalyzed reaction is the formation of carboxylate esters, such as acetates [159,1601. 

Another feasible combination for iron-catalyzed cross-coupling reactions is those of functionalized arylcopper reagents as nucleophiles with alkenyl sulfonates as electrophiles. Tris(acetylacetonato)iron (10 mol%) functions as a precatalyst in this system that tolerates ester or cyano groups. The required arylcopper reagents can be prepared from the corresponding Grignard reagents by treatment with copper(I) cyanide di(lithium chloride) (Scheme 4—217). ... 

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