Silver acetylides synthesis

This methodology was utilized effectively by Inanaga and coworkers in the total synthesis of methynolide.96 Using the silver acetylide in this case allowed for the mild introduction of the acetylenic moiety, avoiding the use of strong base in the presence of the base sensitive ynone product (Scheme 1.36). 

An extension of the original methodology has seen the synthesis of propargylic alcohols in moderate to good yields from silver acetylides via zirconium acetylides (Scheme 1.45).108... 

In the synthesis of nucleosides from their corresponding C-glycosyl derivatives, silver acetylides have been proved effective in introducing an acetylenic ester. The ribose... 

Iodine, bromine, and chlorine react with silver acetylides to give haloalkynes. An early report of such a reaction was applied to the first synthesis of perchloropheny-lacetylene (Scheme 1.58).130,131... 

Since such reactivity has recently been reviewed,8 only a few examples are reported here. Acyl halides or epoxides can be alkynylated with preformed silver acetylides. Such processes have been applied to the total synthesis of the antibiotic macrolide (+ )-methynolide,96 and in the total synthesis of the antitumor agent FR901464 isolated from a Pseudomonas species (Scheme 10.62).97... 

Silver acetylide-silver nitrate was used in light initiated flying plate generator of shock wave experiments at Sandia in 1980 [36, 37]. The use in organic synthesis has been reported by Sladkov and Ukhin [38]. 

Sladkov, A.M., Ukhin, L.Y. Copper and silver acetylides in organic synthesis. Russ. Chem. Rev. 748-763 (1968)... 

The stereospecific reduction of a 2-butyne-l, 4-diol derivative and silver( I)-mediated cyclization of the resulting allene were successively applied to a short total synthesis of (+)-furanomycin 165 (Scheme 4.42) [68], Stereoselective addition of lithium acetylide 161 to Garner s aldehyde in the presence of zinc bromide afforded 162 in 77% yield. The hydroxyl group-directed reduction of 162 with LiAlH4 in Et20 produced the allene 163 stereospecifically. Cyclization followed by subsequent functional group manipulations afforded (+)-furanomycin 165. 

TABLE 2. Enthalpies of formation (AfHm ) and enthalpies of synthesis [Ar m > equation 5] of disilver acetylide silver salt complexes (kJmol-1)... 

Specifically, the synthesis of the cyclohexyl components of the boll weevil sex pheromone featured the Meyer-Schuster reaction of 40, prepared via acetylide addition and acetylation of the resulting tertiary alcohol. Treatment of 40 with silver(I) carbonate in acetic acid resulted in smooth formation of aldehyde isomers 41 and 42 (47 53) in excellent yield. 

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