Photostimulated reactions of organomercurials with alkenes and alkynes

Photostimulated reactions of alkylmercury chlorides with electronegatively substituted alkenes followed by NaBH[subscript]4 reduction afford the hydroalkylation products in good yields. The reactions occur by a free radical chain process involving an intermediate RCH[subscript]2CH(HgCl)Q which has been trapped with molecular iodine to form the iodide RCH[subscript]2CH(I)Q. The relative reactivity of RHgCl in this addition reaction has been measured as t -BuHgCl \u3e i -PrHgCl ~ c -C[subscript]6H[subscript]11HgCl \u3e\u3e n -BuHgCl. The iodide, RCH[subscript]2CH(I)Q, can easily eliminate HI with 1,8-diazabicyclo(5,4,0) undec-7-ene (DBU) to accomplish the conversion of CH[subscript]2=CHQ into RCH=CHQ with high yields. tert -Butyl-mercury chloride reacted with alkynes to give (E) and (Z) adduct olefins in excellent yields. The intermediate t -Bu(X)C=C(HgCl)Y involved in a free radical chain sequence has been converted into t -Bu(X)C=C(I)Y;The determination of the initial kinetic chain lengths indicates that these reactions are definitely radical chain processes. The kinetic study found that the reaction of tert -butylmercury chloride with diethyl vinylphosphonate is a first-order reaction in which the reaction rate only depends on the concentration of t -BuHgCl;The reactions of alkylmercury chlorides with haloalkenes and dihaloalkenes have been studied. Dialkylmercurials were found to react with some haloalkenes to form the alkylated coupled olefins and alkylmercury halide