| A review shows that spiro systems had not been thoroughly examined as chiral auxiliaries for Diels-Alder reactions. 6-(2,2-Dimethylpropamido)spiro[4.4]nonan-1-ol was investigated as an extension of work with cis,cis-spiro[4.4]nonane-1,6-diol for this purpose.;A 10 step stereoselective synthesis of (+)-cis,trans-6-(2,2-dimethylpropamido)spiro[4.4]nonan-1-ol in 29% yield from (±)-ethyl-2-oxocyclopentanecarboxylate is presented. A correction to the previously published baker's yeast reduction of (±)-2-ethoxycarbonyl-2-(2-propenyl)cyclopentanone is reported, where the absolute stereochemistry of the reduction product, 2-ethoxycarbonyl-2-(2-propenyl)cyclopentanol, was assigned to be 1 S,2S by X-ray crystallography. The absolute stereochemistry of (+)-cis,trans-6-(2,2-dimethylpropamido)spiro[4.4]nonan-1-ol was assigned by an X-ray crystal structure of its p-bromobenzoate derivative to be 1R,5S,6S.;Application of (+)-cis,trans-6-(2,2-dimethylpropamido)spiro[4.4]nonan-1-ol as a chiral auxiliary for diastereoselective Diels-Alder reactions is investigated. Moderate to excellent results were obtained using dienophile ester derivatives with a variety of dienes. Diastereomeric excesses greater than 97% (97% ee after cleavage) were obtained in some cases. |
