Organocatalytic Michael addition of 2-nitro methylene imidazolidines to α,β-unsaturated aldehydes: concise synthesis of chiral insecticide Paichongding

An organocatalytic Michael reaction of 2-nitro methylene imidazolidines to α,β-unsaturated aldehydes followed by acetal-amination affords hexahydroimidazo[1,2-a]pyridines in high yields and with moderate to excellent enantioselectivity. The utility of the reaction was illustrated by a one-step transformation to Paichongding, an insecticide of the neonicotinoid family.

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