摘要：

α,β-Unsaturated aldehyde acetals add :CCl 2 (obtained in accordance with Makosza procedure) to form gem-dichlorocyclopropanecarboxaldehyde acetals ( 1) in high yields when the ratio of reactants is no less than 1:4. The addition of :CCl 2 to polyunsaturated aldehyde acetals in the above conditions proceeds regioselectively at double bonds enriched by electrons. Compounds 1 are reduced by sodium in liquid ammonia to give cyclopropanecarboxaldehyde acetals ( 2). Both 1 and 2 are hydrolized by dilute H 3P0 4 to the corresponding aldehydes and are added to vinyl ethers in the presence of BF 3·Et 2O to produce only 1:1 adducts which are hydrolyzed by a mixture of AcOH-AcONa-H 2O to give β-formylcyclopropanes which were previously unknown.

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