Asymmetric vicinal acylation of olefins: A new approach to enantiomerically pure γ-lactones.
摘要:
Amide 3 derived from N-tosylsarcosine and (2R,5R)-dimethylpyrrolidine was converted into keteniminium salt 4 which readily cycloadded to olefins. Hydrolysis of the adducts yielded cyclobutanones which were regiospecifically oxidized to gamma-lactones 7. High enantioselectivities were observed with 1,2-cis-disubstitued olefins.