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

Kazuaki Enomoto, Harufumi Oyama, Masahisa Nakada

Chemistry (Weinheim an der Bergstrasse, Germany) 2015 Feb 9

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Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene β-oxo imides with ynamides are described. The high reactivity of the cyclic α-alkylidene β-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 β-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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Kazuaki Enomoto, Harufumi Oyama, Masahisa Nakada. Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene β-oxo imides with ynamides. Chemistry (Weinheim an der Bergstrasse, Germany). 2015 Feb 9;21(7):2798-802