ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Reaction of diphenyl diketones (benzils) with aryliminodimagnesium [ArN(MgBr)2, IDMg], a magnesium reagent having condensation ability, was investigated. By comparison of the relative amounts of heat evolved in the reactions of IDMg (mildly electron donating) and ArMgBr (strongly electron donating) with some carbonyl and nitro compounds, results were obtained supporting the reported correlation of the relative yields of normal and abnormal (radical) products with single electron transfer (SET) efficiency estimated by the oxidation and reduction potentials of reactants. A sole exceptional result, i.e. the great heat evolution caused by the combination of benzil and IDMg, was attributed to the generation of tightly chelated radicals via SET. The involvement of stepwise SET was confirmed by ESR. On the basis of these results, substituent effects of benzil and mono-condensation products on their reduction potentials and on the relative yields of normal (mono- and di-condensation) and abnormal (dimerization) products were examined. All the results were consistently explained in terms of the relative efficiency of chelation (or σ-complexation) and SET in two main processes. The role of the initial stages involved in the processes governing the final product distribution is discussed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610030606
