Enantioselective addition of activated terminal alkynes to 1-acylpyridinium salts catalyzed by Cu-Bis(oxazoline) complexes

Article abstract of DOI:10.1021/ja0734849

CuI/bis(oxazoline)-catalyzed addition of propiolates and terminal ynones to 1-acylpyridinium salt (generated in situ from reaction of pyridine and methyl chloroformate) affords highly functionalized dihydropyridines with excellent enantioselectivity. It is found that the carbonyl group adjacent to the alkyne moiety is essential for the enantioselectivity of the addition. Short synthesis of indolizidines 167B and 223AB is achieved by employing two addition products. Copyright