13694-96-7Relevant articles and documents
Simple phase transfer catalytic method for α-methoxylation of sterically hindered ketones
Abele,Rubina,Shymanska,Lukevics
, p. 1371 - 1376 (1995)
Reactions of sterically hindered ketones of ArylCOCHR1R2 type (R1, R2 = Me, Et, Ph) with carbon tetrachloride and methyl iodide in the presence of solid KOH and 18-crown-6 afford the corresponding α-methoxyketones [ArylCOC(OMe)R1R2] in one-pot process in 30-67% yields.
Substituent Effects on the Strength of C-C Bonds, 14. - Kinetic and Thermodynamic Stability of 2,3-Bis(dialkylamino)-1,4-diketones - Energy of Stabilization of α-Dialkylamino α-Carbonylalkyl Radicals with Capto-dative Substituents
Welle, Frank,Verevkin, Sergej P.,Keller, Manfred,Beckhaus, Hans-Dieter,Ruechardt, Christoph
, p. 697 - 710 (2007/10/02)
The equilibrium constants and rate constants for the dissociation of the 2,3-bis(dialkylamino)-1,4-diketone diastereomers meso- and DL-7a and 7b were measured over a temperature range of 40 deg C.From the enthalpies of dissociation ΔHDiss and ethalpies of activation ΔH(excit.) and the strain enthalpies of 7 the bond dissociation enthalpies BDE(C-C) of 7 were determined.By comparison with the dissociation enthalpies of Ct-Ct alkanes the change of these BDEs(C-C) by the capto-dative substitution was determined to be 85.4 kJ mol-1 (20.4 kcal mol-1).The heats of formation ΔHf0(g) of a series of amino ketones 8 were determined from their heats of combustion and their heats of evaporation.From the ΔHf0(g) values in combination with MM2 calculations of their strain enthalpies strain-free increments CHn2-n> with n = 0, 1, 2 were derived and geminal interaction enthalpies in the ground states were obtained thereof.The radical stabilization enthalpy RSE of 6 was deduced from the ΔBDE(C-C) values and the ground state effect to be 73.6 kJ mol-1 (17.6 kcal mol-1).From these data and the radical stabilization enthalpies RSE of α-aminoalkyl radicals (4.2 kJ mol-1) and α-carbonyl radicals (28.9 kJ mol-1) a synergetic radical stabilization enthalpy of 40.5 kJ mol-1 (9.7 kcal mol-1) is deduced.This number combines "extra" resonance stabilization and general inductive or anomeric geminal substituent interaction in the radicals.The crystal structure of meso-7a has been determined by X-ray diffraction methods. - Key Words: C-C Bond cleavage, kinetics of / Heats of formation / Radicals, stability of / Capto-dative effect / Geminal substituents, energetic interaction of
Silver ion induced reactions of α-haloimines
De Kimpe, Norbert,Stevens, Christian
, p. 6753 - 6770 (2007/10/02)
The silver ion induced reactions of α-haloimines are markedly different from similar reactions with the corresponding α-haloketones. The various reactions of α-haloimines, including α-alkoxylation 1,2-dehydrohalogenation, rearrangement via α-alkoxyaziridines, Favorskii-rearrangement and Wagner Meerwein rearrangement, are compared and evaluated with silver-induced reactions of α-haloketones The silver ion assisted reactions of α-haloimines are best interpreted in terms of the intermediacy c α-imidoylcarbenium ions or pseudo-α-imidoylcarbenium ions.
