STEREOCHEMISTRY OF ADDITION OF MERCURY SALTS TO ALKYNES

Reactions of Hg(OOCR)(2) (R = Et, Pr-n, Pr-i, and Bu-n) with methylphe nylacetylene (with the corresponding acids as solvents) give mixtures of cis- and trans-adducts. The quantity of the cis-adduct increases wi th increase in the length of the acyl substituent. syn-Addition also o ccurs in the acetoxymercuration of m-chlorophenyl(methyl)acetylene and 1-methoxybut-2-yne; in the latter case, this route predominates. The stereochemistry of the reaction can also depend on the ratio of the re actants. It is proposed that the reaction occurs by several schemes in which these factors manifest themselves in different degrees.