1,3-Butadiene, reactions with recoil

We were faced with a dilemma six years ago when the major product from reactions of recoiling silicon atoms with butadiene turned out to be one for which no authentic sample could be synthesized (4,39). 

Formation of l,2,3 Pentatriene from Recoil Atom Reactions with 1 3 Butadiene... 

Formation of l-Silacyclopenta-2,4-diene through Recoil Si Atom Reactions with 1,)-Butadiene... 

In our laboratory, we have studied recoil Si reactions with butadiene by using PF3 as the Si precursor. From the formation of [ Si]-l,l-difluorosilacyclopent-3-ene as a product, we reasoned that SiFj was formed through stepwise F abstraction by recoil Si atoms as shown in equations (8) and (9). An insertion-decomposition mechanism similar to that shown in equation (7) is also possible. 

The best studied addition reactions of silylene have been those with conjugated dienes. Earlier studies using the nuclear recoil system have shown that 31SiH2 added to 1,3-butadiene to give silacyclopent-3-ene (44, 99, 100). 

Direct interaction of recoil atoms or fragments, obtained in the C(y,n) C process with various Cg hydrocarbons, resulted in the formation of C-labelled methane, acetylene, ethane + ethylene, propane + propylene and l,3-butadiene Methane- and acetylene- have been produced in the radiochemical reaction between and liquid benzene, with the yield ratio (CH4/C2H2) being in the range of 0.02 to 0.03. 

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