A Practical Synthesis of 1,2-Nitroamines by Michael Addition of N-Nucleophiles to Nitroalkenes

Abstract

A practical method for the synthesis of a-nitroamines by Michael addition of azide to nitroalkene has been developed. This reaction proceeds in high yields under very mild conditions (phasetransfer catalysis) and is found to be general; good yields are obtained with both aryl and alkyl derivatives as well as with 1,1-disubstituted ones.

Asymmetric Hydroazidation of Nitroalkenes Promoted by a Secondary Amine‐Thiourea Catalyst

“…The solvent was removed under reduced pressure and the residue was purified by flash chromatography (silica gel, eluent: petroleum ether/diethyl ether 95:5 to 90:10). The characterization data of the products 2a–g were identical to those previously reported 10,30. The enantiomeric excesses were determined by chiral HPLC as described below.…”

A versatile and efficient approach for the synthesis of chiral 1,3-nitroamines and 1,3-diamines via conjugate addition to new (S,E)-γ-aminated nitroalkenes derived from L-α-amino acids

“…The formation of chiral 1,2,3-triazole derivative 11a was proposed to be by way of a [3 + 2]-cycloaddition with the azide group acting as 1,3-dipolarophile, followed by HNO 2 elimination leading to aromatization. There are a few reports in the literature where the azide anion is added to α,β-unsaturated nitroalkenes [8,19–22] forming 1,4-adducts [8] or 1,2,3-triazole derivatives [31–33]. Apparently, the reaction course depends on the temperature and concentration of the azide reagent used.…”

Revision of the Structure and Total Synthesis of Topsentin C

“…Reduction of the adducts of α,β-unsaturated nitrocompounds with amines, O -alkylhydroxylamines or azide anion was proposed earlier for the synthesis of vicinal diamines. 11 12 13 The first type of adduct was unstable, although they could be isolated as the more stable salts. 11 Adducts with O -alkylhydroxylamines or azide anion were more stable.…”

“… 11 Adducts with O -alkylhydroxylamines or azide anion were more stable. 12 13 However, catalytic hydrogenation or heating with Zn dust in HOAc was required to cleave the hydroxylamine N–O bond. 12 Catalytic hydrogenation was also used to reduce the azido group.…”

“…12 Catalytic hydrogenation was also used to reduce the azido group. 13 The proposed methods turned out to be ineffective for the synthesis of Br-containing (indol-3-yl)ethane-1,2-diamines 6 . Thus, the products 10 from the reaction of methylamine or benzylamine with nitrovinylindole 9b could not be isolated; starting 9b was recovered and the reaction mixture formed a resin.…”