Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene ß-oxo imides with ynamides.

Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene ß-oxo imides with ynamides are described. The high reactivity of the cyclic α-alkylidene ß-oxo imide allows the [2+2] cycloadditions of a hindered substrate with unreactive ynamides at low temperature. The X-ray crystallographic analysis of the product suggests that the enantioselectivity of the [2+2] cycloaddition can be well explained by the chelate model comprising the intramolecular hydrogen bond, wherein the cyclic α-alkylidene ß-oxo imide coordinates with Cu(II) through the two imide carbonyls. The imide group in the product can be transformed to amide, nitrile, and ester groups; moreover, it is removable.

Catalytic asymmetric [4 + 2] cycloadditions and Hosomi-Sakurai reactions of α-alkylidene ß-keto imides.

Highly enantioselective catalytic asymmetric reactions of rationally designed α-alkylidene ß-keto imides are described. The [4 + 2] cycloadditions and Hosomi-Sakurai reactions of α-alkylidene ß-keto imides proceed with high enantioselectivity and yield. The [4 + 2] cycloadditions of the imides with various dienes afford products bearing an all-carbon quaternary stereogenic center at the ring junction. α-Alkylidene ß-keto imides should be useful for the enantioselective total synthesis of natural products and other catalytic asymmetric applications.