Total Synthesis of Donaxaridine

Abstract

The first total synthesis of donaxaridine (1) is reported.

Facile Creation of 3-Substituted-3-Hydroxy-2-Oxindoles by Arginine-Catalyzed Aldol Reactions of α,β-Unsaturated Ketones with Isatins

“…The simple amino acids bearing only an amino group and a carboxyl group could not catalyze this reaction. No expected aldol adducts were observed after direct determination by TLC (Table 1, entries [1][2][3][4][5]. This indicated that it is impossible for the aldol reaction in which these primary amine and secondary amine catalysts unilaterally activate the (E)-4-phenylbut-3-en-2-one (2a) to form an enamine intermediate.…”

“…The electronic properties and steric hindrance of the substituents at the aromatic ring influenced the yields slightly. Generally, α,β-unsaturated ketones with electron-donating groups gave higher yields than those with electron-withdrawing groups (Table 2, entries 2, 10 vs. [3][4][5][6][7][8]. Ortho-and meta-substituted α,β-unsaturated ketones gave higher yields than para-substituted α,β-unsaturated ketones ( Table 2, entries 2-5 vs. [8][9][10][11].…”

“…This kind of compounds have become important synthetic targets as these structural frameworks form the core units of many natural products and pharmaceutically active compounds [1]. Convolutamydines [2], arundaphine [3], donaxaridine [4], dioxibrassinine [5], maremycins [6], paratunamide [7], celogentin K [8], TMC-95A-D [9], flustraminol [10], 3-hydroxy welwitindolinones [11] and CPC-1 [12] are some examples of a growing list of bioactive 3-substituted-3-hydroxy-2-oxindole natural products (Figure 1). …”

Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles

“…Chiral High-performance liquid chromatography (HPLC) analysis was conducted with a Waters Alliance 2695 instrument (Waters corporation, Milford, MA, USA), using a UV-visible light (Vis) Waters PDA 2998 detector (Waters corporation), and working at 254 nm. 1 H NMR spectra were recorded on a Bruker AM400 NMR spectrometer (Bruker corporation, Karlsruhe, Germany), and NMR spectra were obtained as CDCl3 solutions (reported in ppm), using chloroform as the reference standard (7.26 ppm) or dimethyl sulfoxide-d6 (DMSO-d6)(2.50 ppm). High-resolution mass …”

“…The 3-substituted-3-hydroxy-2-oxindoles have a stereogenic quaternary center at the C-3 position and a core unit that appears in many natural products and biologically active compounds [1][2][3][4][5][6][7][8].…”