One‐Pot Synthesis of Aliphatic Nitro Compounds by Michael/retro‐Claisen Fragmentation Domino Reaction

Abstract

A novel and concise method for the construction of γ-nitro ketones and 1,3-dinitro compounds with chemoselective acyl transfer has been presented under basic conditions via one-pot reactions. These reactions feature high atom-and step-economic possess, mild condition and simple operation for one-pot synthesis of aliphatic nitro compounds. This protocol provides the products in good yields. The possible reaction mechanism has also been proposed.

Organocatalytic Asymmetric Michael–Acyl Transfer Reaction of α‐Nitroketones with 2‐Hydroxybenzylidene Ketones

“…2‐(( S )‐1‐nitro‐4‐oxopentan‐2‐yl)phenyl benzoate (3a): Yellow sticky solid (23 mg, 70 % yield); R f value 0.3 (1:1 Hex/DCM); 1 H NMR (600 MHz, CDCl 3 ) δ = 8.25 (dd, J = 8.3, 1.3 Hz, 2H), 7.71–7.66 (m, 1H), 7.59–7.53 (m, 2H), 7.36 (ddd, J = 8.1, 6.7, 2.4 Hz, 1H), 7.31–7.26 (m, 2H), 7.21 (dd, J = 8.1, 0.8 Hz, 1H), 4.69 (d, J = 7.1 Hz, 2H), 4.27–4.21 (m, 1H), 2.95–2.84 (m, 2H), 2.09 (s, 3H); 13 C NMR (150 MHz, CDCl 3 ) δ = 205.4, 165.5, 149.0, 134.3, 131.2, 130.5, 129.2, 129.1, 128.2, 126.9, 123.6, 78.5, 45.5, 33.3, 30.4; ESI‐MS : m/z calcd. for C 18 H 17 NaNO 5 [M + Na] 350.1004, found 350.0997; FT‐IR (KBr) : 2921, 2851, 1741, 1604, 1557, 1493, 1323, 1200, 1173, 1113, 1062, 1023 cm –1 ; The ee values 99 % (t major = 40.83 min, t minor = 46.85 min) was determined by HPLC using Daicel Chiralpak IB with hexane/ i PrOH (97:3) as the eluent, flow: 1.0 mL/min, 220 nm, 25 °C; Optical Rotation : [ α ] D 26.2 = –0.004 ( c = 0.875, CHCl 3 ).…”

The chemistry of 2-hydroxy-β-nitrostyrenes: versatile intermediates in synthetic organic chemistry

“…40 The fragmentation domino reaction of active methylene compounds 71 with 2-hydroxy-β-nitrostyrenes 2 was investigated by Zhang et al This reaction was efficiently catalyzed by triethylamine to afford the useful building blocks, such as γ-nitro ketones and 1,3-dinitro compounds 72 via an acyl transfer reaction (Scheme 25). 41 This reaction follows the principles of green chemistry such as atom-and step-economies and takes place under moderate circumstances. Screening of the bases and solvents reveals that the best yield was obtained in CH 3 CN in the presence of 10 mol% Et 3 N at room temperature.…”

One-pot cascade reactions for the synthesis of dinitroalkanes in aqueous buffer

“…In both approaches, a basic catalyst is required to activate the nitroalkane, often triethylamine or a metal-based catalyst (e.g., Al 2 O 3 ). [6][7][8] To bias the reaction toward the dinitroalkane, it is common to supply the nitroalkane in large excess (>50 molar equivalents) 9,10 or even as the reaction solvent. 3,7 Moreover, because of the multi-step nature of the reactions, the intermediate nitroalcohol and/or nitroalkene are typically isolated after each step, increasing complexity and resource requirements.…”