Acetals of Ring-Contracted Cycloalkyl Aldehydes

Cycloalkenes to Acetals of Ring-Contracted Cycloalkyl Aldehydes 

When 2-methoxycycloalkyl phenyl telluriums, prepared from cycloalkenes and phenyl tellurium trichloride in methanol, are treated with 3-chloroperoxybenzoic acid, the elimination of the phenyltelluro group is accompanied by ring-contraction and formation of the dimethyl acetals of formylcycloalkanes  

When tra j-2-methoxycyclohexyl phenyl tellurium was treated with 2 molar equivalents of sodium periodate in aqueous methanol, formylcyclopentane was isolated in 75% yield. fra 5-2-Methoxycycloheptyl phenyl tellurium and an excess of sodium periodate, hydrogen peroxide, or ter/.-butyl hydroperoxide in aqueous methanol produced mixtures of the dimethyl acetal of formylcyclohexane, cyclohexylformaldehyde, and methoxy-2-cyclo-heptene.  

2-Methoxy-2-phenylethyl phenyl tellurium was oxidized to the dimethyl acetal of phenylacetaldehyde by one molar-equivalent of 3-chloroperoxybenzoic acid in methanol.  

The oxidation of t/ fl 5-2-hydroxycyclohexyl phenyl tellurium with ten molar-equivalents of 3-chloroperoxybenzoic acid in methanol produced cyclopentylformaldehyde in 74% yield and cyclohexanone in 10% yields 

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