Asymmetric synthesis of 3-prenyl-substituted pyrrolidin-2-ones

Investigations towards the stereoselective organocatalyzed Michael addition of dimethyl malonate to a racemic nitroalkene: possible route to the 4-methylpregabalin core structure

“…Enantiomerically enriched Michael adduct 7 , which was obtained with catalyst ( S , S )- C5 , was also used to finish the synthesis of 4-methylpregabalin ( 1 ) in an analogy to literature procedures ( Scheme 4 ) [ 47 ]. Adduct 7 was transformed to lactone 13 via nitro group reduction with NaBH 4 /NiCl 2 followed by spontaneous lactamization.…”

Fluoride Additive as a Simple Tool to Qualitatively Improve Performance of Nickel-Catalyzed Asymmetric Michael Addition of Malonates to Nitroolefins

“…13 C {1H} NMR (101 MHz, CDCl 3 ): δ 168.0, 167.4, 150.0, 147.7, 128.2, 120.0, 114.7, 112.0, 80.5, 77.8, 55.9, 54.9, 53.0, 52.9, 42.7, 32.8, 24.1. NMR spectra are in agreement with the literature data …”

“…mp 95−96 °C. 1 57 Dimethyl (R)-2-(4-Methyl-1-nitropentan-2-yl)malonate (1m). A 10 mL screw-cap Schlenk tube with a stirring bar was prepared according to a standard Schlenk procedure, and 15 mg (5 mol %) of the precatalyst NiBr 2 -Cat-2 was placed inside as an aliquot in chloroform followed by the addition of 9.48 mg (4 mol %) of TBAT as an aliquot in chloroform.…”

Selective One‐Pot Two‐Step C−C Bond Formation using Metal–Organic Frameworks with Mild Basicity as Heterogeneous Catalysts

“…Finally, the nitro groups can be further reduced to obtain the GABA or tryptamine scaffold, respectively. The replacement of soluble catalysts– by heterogeneous counterparts simplifies the removal of the catalyst from the reaction mixture and may allow its reuse . Herein, a new family of post synthetically modified metal–organic frameworks is employed to selectively direct the different C−C bond‐forming reactions towards desired products 2 and 3 starting from benzaldehyde and nitromethane as starting materials.…”