Stereoselective hetero Diels-Alder reactions of chiral tricarbonyl(eta-6-benzaldehyde)chromium complexes

The ZnCl2-promoted cycloaddition of a series of enantiopure ortho-substituted benzaldehyde-Cr(CO)3 complexes and Danishefsky's diene gave the corresponding 2-aryl pyranones in good yields and complete enantiospecificity. Some of the mechanistic aspects of the cycloaddition were investigated and the reaction extended to different dienes