[Karina280594]

Hey,

Could someone help me with the mechanism of this reaction:

Styreneoxide reacting with acetone to give 2,2-dimethyl-4-phenyl-1,3-dioxolane and Cu(OTf)2 is an Lewis acid in the reaction??

[AWK]

TReaction of formation of acetonides with epoxides is well known. Search literature and show us your attempt.

[Karina280594]

TReaction of formation of acetonides with epoxides is well known. Search literature and show us your attempt.

So my attempt would be like shown on the picture. I'm a bit confused about how the epoxide would act. Do the epoxide open before the acetone attack?

[AWK]

Do the epoxide open before the acetone attack?

I only know that in presence TiCl₃OTf as catalyst this reaction is higly stereospecific, and almost non-stereospecific with anhydrous CuSO₄.
In the case of racemic oxirane it does not matter.

[Karina280594]

Do the epoxide open before the acetone attack?

I only know that in presence TiCl₃OTf as catalyst this reaction is higly stereospecific, and almost non-stereospecific with anhydrous CuSO₄.
In the case of racemic oxirane it does not matter.

Allright! Thanks! :-)

[orgopete]

I don't mean to buump this old mechanism, but for what it might be worth, I doubt formation of an alkoxide intermediate. It seems more likely to me that a ROCu^-(OTf)₂ copper would eliminate a triflate rather than an alkoxide. Such a mechanism would require a somewhat more lengthy mechanism, but I feel would be more likely.