Doubly Stereocontrolled Asymmetric Aza-Henry Reaction with in situ Generation of N-Boc-Imines Catalyzed by Novel Rosin-Derived Amine Thiourea Catalysts

The doubly stereocontrolled organocatalytic aza-Henry reaction of nitroalkanes to N-Bocimines generated in situ from a variety of substituted alpha-amido sulfones was investigated for the first time, in general, affording the corresponding products with high to excellent yields (up to 93% yield) and enantioselectivities (up to 98% ee), and satisfactory diastereoselectivies (anti/syn up to 98:2). Furthermore, these organocatalysts based on rosin have been proved to be the very effective promoters for this catalytic asymmetric process along side the Cinchona alkaloid-derived catalysts.