Highly enantioselective synthesis of gamma-nitro heteroaromatic ketones in a doubly stereocontrolled manner catalyzed by bifunctional thiourea catalysts based on dehydroabietic amine: a doubly stereocontrolled approach to pyrrolidine carboxylic acids.

A new class of dehydroabietic amine-substituted primary amine-thiourea bifunctional catalysts were designed and synthesized. The doubly stereocontrolled organocatalytic conjugate addition of a variety of heterocycles-bearing ketones to nitroalkenes was investigated for the first time, affording (S)- or (R)-gamma-nitro heteroaromatic ketones with excellent enantioselectivities (up to ee >99%). Furthermore, the nearly optically pure gamma-nitro heteroaromatic ketones can be readily transformed into chiral pyrrolidine carboxylic acids.