Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates

• Ekta Gupta,
• Narendra Kumar Vaishanv,
• Sandeep Kumar,
• Raja Krishnan Purshottam,
• Ruchir Kant and
• Kishor Mohanan

Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25

• of enantioselectivity, and the corresponding optically active oxyaminated malonamates were obtained in reasonably good yields. Keywords: enantioselective; malonamate; nitroso aldol reaction; N-selectivity; Takemoto catalyst; Introduction Nitrosoarenes are versatile building blocks frequently

• reported a squaramide-catalyzed asymmetric nitroso aldol reaction of cyclic β-ketoesters and malonamate [61]. Inspired by this, we decided to investigate the use of malonamate in the asymmetric nitroso aldol reaction using thiourea catalysis. Herein, we report a novel nitroso aldol reaction of malonamates

• optimal reaction conditions, we proceeded to evaluate the generality of this nitroso aldol reaction with respect to the amide component of malonamate (Scheme 2). Pleasingly, our strategy was found to be operational with malonamates bearing electronically different substituents such as halo, nitro, acetyl

Towards the total synthesis of keramaphidin B

• Pavol Jakubec,
• Alistair J. M. Farley and
• Darren J. Dixon

Beilstein J. Org. Chem. 2016, 12, 1096–1100, doi:10.3762/bjoc.12.104

• piperidin-2-one 17 in 71% yield. Lactonisation under Lewis acidic conditions afforded spirocyclic malonamate 18 possessing the correct relative stereochemistry for keramaphidin B, in 84% yield. Aminolysis under neat conditions with hex-5-en-1-amine (19) gave the primary alcohol 20 (67% yield), which was