1.1- Diphenylethylene epoxide

Due to the high reactivity of sulfonium ylide 2 for a,P-unsaturated ketone substrates, it normally undergoes methylene transfer to the carbonyl to give the corresponding epoxides. However, cyclopropanation did take place when 1,1-diphenylethylene and ethyl cinnamate were treated with 2 to furnish cyclopropanes 53 and 54, respectively. 

Soveral 1,1-diarylethylcne oxides have been subjected to Ihr action of magnesium bromide or boron trifluoride (Eq. 453). Again, migratory aptitude in the epoxide-isomerization process appears to l -a function of the overall substitution pattern. Thus, 1,1-diphenyi ethylene oxide and 2-methyl-1,1 -diphenylethylene oxide -J suffer hydride shifts exclusively. On the other hand, 2-ethyl-i.i-diphenylethylene oxide reportedly undergoes hydride shift and cthvl migration... 

The perhydrolysis of other epoxides and subsequent condensation follow the same reaction course. Styrene epoxide affords 3,6-diphenyl-l,2,4-trioxane <76CC508>. Other simple epoxides, for example those obtained from ispropene and 1,1-diphenylethylene, are also similarly convertible into trioxanes <71CC822>. 

The most efficient synthesis of an epoxide-functionalized macromonomer (97% yield, no dimer) was obtained by first end-capping poly(styryl)lithium with 1,1-diphenylethylene as shown in Scheme 11. The decreased reactivity and increased steric requirements of the diphenylalkyllithium chain end promoted selectivity and decreased the formation of dimer in this epoxide functionalization reaction. 

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