syn-Diastereoselective conjugate addition of 1-pyrroline esters to nitroalkenes in good yields with an excellent enantioselectivity by using CuOAc/Me-FcPHOX catalyst in the presence of pyridine. In contrast, AgOAc/tBu-ThioClickFerrophos catalyzed the anti diastereoselective conjugate addition with a high enantioselectivity without additional base. Thus, the preparation of chiral 1-pyrroline derivatives bearing diverse stereochemistry could be achieved. The diastereoselective reduction of the imine group in the conjugate adduct could afford the 2,5-cis-proline ester derivative.

The copper-catalyzed asymmetric conjugate addition of 2-oxazoline- and 2-thiazoline 4-carboxylate to a nitroalkene proceeded to give either the syn or anti adduct selectively in high enantiomeric excess when an appropriate chiral ligand was used. Subsequent reduction of the nitro group followed by hydrolysis of the oxazoline ring yielded an optically active gamma-lactam of protected alpha-quaternary serine derivative.

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A AgOAc/ThioClickFerrophos complex-catalyzed the highly diastereo- and enantioselective reaction between 1-pyrroline-5-carboxylates (1) and acyclic α-enones (2) in MeOH, in the presence of DBU, to give the single isomer Michael adducts (3) in high yields (up to 99%) with excellent enantioselectivies (up to 99% ee). Subsequent reduction of the Michael adducts with sodium cyanoborohydride successfully produced the fused pyrrolizidine ester as an almost pure single stereoisomer.

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