Demercuration amidomercuration

There are several methods available for the electrophilic addition of hydrogen and nitrogen to alkenes, dienes and alkynes. While the direct electrophilic addition of amines to these substrates is not feasible, aminomercuration-demercuration affords a very useful indirect approach to such amines. The addition of amides to C—C multiple bonds can be effected directly through the Ritter reaction or by the less direct, but equally useful, amidomercuration-demercuration process using either nitriles or amides. Similarly, H—N3 addition to alkenes can be carried out directly or via mercuration to produce organic azides. 

Azasilacyclopentanes are most conveniently prepared by the amidomercuration-demercuration of dimethyl(chloroalkyl)alkenylsilanes of the form (131) <87JOM(326)i59,85ZOB706). Thus, treatment of dimethyl(chloromethyl)vinylsilane (Ola, n = 0) or dimethyl(chloromethyl)allylsilane (131b, n = 1) with aniline in THF in the presence of mercury acetate, followed by reduction with sodium borohydride, afforded the azasilacyclopentanes (Ola), (132b). 

Considering the monoaminomercuration-demercuration of 1,4-hexadiene with /V-me-thylaniline leads to V-methyl-lV-(l-methylpent-3-enyl)aniline, the stereoselective synthesis of /V-alkoxycarbonyl or /V-tosyl s-2,5-dimethylpyrrolidine from the same diene has been explained172 on the basis of an initial amidomercuration reaction on the terminal bond followed by the second addition of mercury(II) salt to the internal double bond, on the less sterically hindered site (equation 171). 

Amidomercuration. The reaction of alkenes with anhydrous Hg(N03)2 in the presence of primary amides in CH2C12 followed by demercuration (NaBH4-NaOH- -BuNH2) results in N-substituted amides in 45-99% yield (equation I). 

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