Oxychlorination of alkenes by chlorochromate reagents: A facile preparation of α-chloroketones, and competition by substituent-directed oxidation.

Chiral Polycyclic Ketones via Desymmetrization of Dihaloolefins

“…The crude reaction product was purified by Kugelrohr giving ( R )- 1a (90 mg, 83%, ee = 98%, GC) as oil. Spectral data were identical to those reported in literature: IR (neat) ν max (cm -1 ) 1758 stretching CO (lit 12c. 1750); [α] D = +518 ( c = 0.26, CHCl 3 ); 1 H NMR (CDCl 3 , 400 MHz) δ 6.57 (1H, m), 6.22 (2H, m), 4.10 (1H, d, J = 3.5 Hz), 3.33 (1H, m), 3.22 (1H, m), 2.38 (1H, dm, J = 10.2 Hz), 2.07 (1H, dm, J = 10.2 Hz); 13 C NMR (CDCl 3 , 100 MHz) δ 206.8, 140.7, 131.3, 56.9, 54.6, 46.2, 45.8; MS (EI, 70 eV) m / z 142 (M + , 40), 113 (6), 79 (100), 66 (75), 51 (45) 39 (55).…”

“…We present in this paper an evolution of the original protocol, which uses the dichloroolefin 2a , instead of the sulfonyl olefin 2b , to produce the ketone 1a (a synthetic equivalent of 1b ) in the key desymmetrization step (Scheme ). As 2a was used as a precursor of 2b in the first report, the new synthetic route presents, according to the atom-economy rule, the advantage of significantly reducing the molecular weights of the reagents (i.e., the number of atoms) and the number of steps.…”

Crystal structure and Hirshfeld surface analysis of 1,2-ethylene-bis(para-methylpyridinium) dichromate as a new selective and mild agent in oxidation of alcohols

“…It has been shown that the nature of amine-based cations determines the oxidizing power of the dichromate salts, which is inversely related to the donor strength of the amines. 13 The cation changes the pH value of the salt, which affects its oxidation property, as the electromotive force value of dichromate is strongly influenced by the concentration of H + (the half-cell of Cr the Scheme, and its performance in the oxidation process of various types of alcohols (benzylic, allylic, and saturated) was examined. The synthesized agent includes a bulk protecting organic dication with a low acidic characteristic, which leads to a selective oxidation property.…”

“…It has been shown that the nature of amine-based cations determines the oxidizing power of the dichromate salts, which is inversely related to the donor strength of the amines. 13 The cation changes the pH value of the salt, which affects its oxidation property, as the electromotive force value of dichromate is strongly influenced by the concentration of H + (the half-cell of Cr Although many chromium(VI) reagents are available for the oxidation of organic substrates, there still ex- The structure of the reagent was studied by single-crystal X-ray diffraction experiments, and the detailed investigation of intermolecular contacts was explored by Hirshfeld surface (HS) analysis and fingerprint plots.…”

Epoxidation of substituted norbornenes. Stereochemical aspects and accompanying intramolecular transformations

“…71 The use of cyanopyridinium chlorochromate as the oxidant for norbornene and other cycloalkenes leads to products of another type, namely, chloro ketones. 78 Agarval et al have studied oxidation of cycloalkanes catalysed by Fe(III), 79 Cr(III), 80 Mn(III), 81,82 and Ru(III) 83 complexes with Schiff bases. Later, manganese complexes with Mannich bases have also been tested as catalysts for this reaction.…”