Asymmetric 1,3-dipolar cycloadditions of chiral carboxyloyl nitrile oxides to cycloalkenes

Asymmetric 1,3-dipolar cycloadditions of chiral carboxyloyl nitrile oxides derived from (2R)-bornane-10,2-sultam, (1R)-8-phenylmenthol, N,N-dicyclohexyl-10-sulfamoyl-(2R)-isoborneol, and 7,7-dimethylnorbornane-(1S,2R)-oxazolidinone to four cycloalkenes, leading to the corresponding 2-isoxazolines in both moderate yields and diastereoselectivities, are presented. All cycloadducts were converted into the corresponding alcohols, which were used for the determination of enantiomeric purity via chiral gas chromatography. In the case of the six-membered ring cycloadduct, the absolute configuration was determined by X-ray analysis. (c) 2007 Published by Elsevier Ltd.