Zinc homoenolates cyclopropane synthesis

Among isolable metal homoenolates only zinc homoenolates cyclize to cyclopropanes imder suitable conditions. Whereas acylation of zinc alkyls makes a straightforward ketone synthesis [32], that of a zinc homoenolate is more complex. Treatment of a purified zinc homoenolate in CDCI3 with acid chloride at room temperature gives O-acylation product, instead of the expected 4-keto ter, as e single product (Eq. (22) [33]). The reaction probably proceeds by initial e ectro-philic attack of acyl cation on the carbonyl oxygen. A C-acylation ... 

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