Hypervalent iodine(III)-induced methylene acetoxylation of 3-oxo-N-substituted butanamides

Abstract

Summary1-Carbamoyl-2-oxopropyl acetate derivatives were synthesized through an acetoxylation process to methylene with the aid of (diacetoxyiodo)benzene (DIB) as the oxidant. Not only mild reaction conditions, but also excellent yields and good substrate scope make the present protocol potentially useful in organic synthesis.

Negatively Charged π‐Electronic Systems by Deprotonation of Hydroxy‐Substituted Dipyrrolyldiketone Boron Complexes

“…Herein, α‐unsubstituted 1 a and α‐phenyl‐substituted 1 b were initially investigated as anion‐responsive π‐electronic molecules substituted with a hydroxy moiety. The introduction of an acetoxy group to dipyrrolyldiketones 1 a′ , b′ was achieved using diacetoxyiodobenzene (DIB), affording meso ‐acetoxy‐substituted 2 a , b in 68 % and 20 % yields, respectively (Figure b) . They were converted into BF 2 complexes 3 a , b in 65 % and 38 % yields, respectively, by treating with BF 3 ⋅OEt 2 .…”

“…According to a literature procedure for related reactions, to a 1,2‐dichloroethane solution (3 mL) of 1,3‐dipyrrol‐2‐yl‐1,3‐propanedione 1 a′ (101 mg, 0.50 mmol) was added diacetoxyiodobenzene (210 mg, 0.65 mmol), and the mixture was stirred under N 2 for 2 h. The reaction mixture was evaporated and the residue was chromatographed over silica gel column (Wakogel C‐300; 5 % MeOH/CH 2 Cl 2 ), then chromatographed over silica gel flash column (45 % EtOAc/ n ‐hexane) to afford 2 a (88.5 mg, 0.34 mmol, 68 %) as a red slurry. R f =0.39 (45 % EtOAc/ n ‐hexane); 1 H NMR (600 MHz, [D 6 ]DMSO, 20 °C): δ =12.05 (s, 2 H; NH), 7.20–7.17 (m, 4 H; pyrrole‐H), 6.51 (s, 1 H; CH), 6.25–6.23 (m, 2 H; pyrrole‐H), 2.17 ppm (s, 3 H; CH 3 ); 13 C NMR (151 MHz, [D 6 ]DMSO, 20 °C): δ =179.32, 169.22, 129.00, 127.45, 119.14, 110.58, 78.30, 20.50 ppm; MALDI‐TOF‐MS: m / z (%): 259.9 (100) [ M ] − ; HRMS (ESI‐TOF): m / z : 259.0698 [ M −H] − .…”

“…One of the advantages of the introduction of ah ydroxy moiety to the boron complexes of dipyrrolyldiketones can be attribut- ed to the studies of variousa nion-responsive p-electronic molecules reported thus far.H erein, a-unsubstituted 1a and aphenyl-substituted 1b [4] were initially investigated as anion-responsive p-electronic molecules substituted with ah ydroxy moiety.T he introduction of an acetoxyg roup to dipyrrolyldiketones 1a',b' [4] was achievedu sing diacetoxyiodobenzene( DIB), affording meso-acetoxy-substituted 2a,b in 68 %a nd 20 % yields, respectively ( Figure 1b). [12] They were converted into BF 2 complexes 3a,b in 65 %a nd 38 %y ields, respectively,b y treating with BF 3 ·OEt 2 .S ubsequenth ydrolysis of the acetoxy group using KOH provided the corresponding meso-hydroxysubstituted 4a,b in 62 %a nd 80 %y ields, respectively (Figure 1b). BF 2 complexes 3a,b and 4a,b along with 2a,b are the first examples of dipyrrolyldiketone derivatives substituted with ah eteroatom, oxygen in this study,a tt he meso position.…”

“…According to al iterature procedure for related reactions, [12] to a1 ,2-dichloroethane solution (3 mL) of 1,3-dipyrrol-2-yl-1,3-propanedione 1a' [4a] (101 mg, 0.50 mmol) was added diacetoxyiodobenzene (210 mg, 0.65 mmol), and the mixture was stirred under N 2 for 2h.T he reaction mixture was evaporated and the residue was chromatographed over silica gel column (Wakogel C-300;5% MeOH/CH 2 Cl 2 ), then chromatographed over silica gel flash column (45 %E tOAc/n-hexane) to afford 2a (88. . a) i) Molecular structure and ii)single-crystal X-ray structure of the transformed anionic species 5a À À obtained from the deprotonated 4a À À as as alt of TBA + ,w hich is omittedf or clarity.Atom colorc ode:b rown, pink, yellow,g reen, blue, and red refer to carbon, hydrogen, boron, fluorine,nitrogen,and oxygen, respectively;b)Expected mechanism of the transformation from 4a À À to 5a À À ; [17] c) Solid-state packing diagram of the ionpair 5a À À ·TBA + : i) charge-by-charge assembly of 5a À À and TBA + and ii)intramolecular and intermolecular hydrogen bonding of 5a À À .…”

Practical method to obtain α-acetoxyketones promoted by (diacetoxyiodo)benzene and acetic acid

“…In addition, some different methods have been developed to synthesize -acetoxyketones, and some of the relevant examples are as follows: the catalysis of iodobenzene with hydrogen peroxide, acetic anhydride and boron trifluoride-diethyl ether; 14 palladium acetate as a catalyst and (diacetoxyiodo)benzene as an oxidant in acetic acid; 15 ketoxime derivatives with trimethyloxonium fluoroborate, triethylamine and aqueous acid; 16 (diacyloxyiodo)benzene with m-chloroperbenzoic acid 17 and thallium(III) triflate in amide solvents; 18 [hydroxy(p-nitrobenzene-sulfonyloxy)iodo]benzene 19 and terminal alkynes with (diacetoxyiodo)benzene catalyzed with silver(I); 20 and enone oxidation with Mn(III) acetate; 21 as well as the synthesis of 1-carbamoyl-2-oxopropyl acetate derivatives with the aid of (diacetoxyiodo)benzene. 22 In the present research, we focus on the synthesis of -acetoxyketones. One of the best methods to obtain these compounds is one that uses stable reactants with low toxicity that are easy to handle, and for this reason, hypervalent iodine derivatives have attracted attention.…”