Synthetic and mechanistic investigation of new radical processes: reaction of organic azides with group-XIII Lewis acids

Bencivenni, Giorgio (2008) Synthetic and mechanistic investigation of new radical processes: reaction of organic azides with group-XIII Lewis acids, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Scienze chimiche, 20 Ciclo. DOI 10.6092/unibo/amsdottorato/1052.
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Abstract

Dichloroindium hydride revealed to be a valid alternative to tributyltin hydride for radical reduction of organic (alkyl, aryl, acyl, solfonyl) azides. The new approach entails mild reaction conditions and provides high yields of the corresponding amines and amides, also showing high degrees of selectivity. The system dichloroindium hydride / azides can be utilised in fivemembered ring closures of g-azidonitriles, as a new source of aminyl radicals for the attractive synthesis of interesting amidine compounds in the absence of both toxic reagents and tedious purification procedures. Allylindium dichloride seems a good substitute for dichloroindium hydride for generation of indium centred radicals under photolytic conditions, since it allows allylation of electrophilic azides (e.g. phenylsulfonyl azide) and halogen or ester δ-substituted azides, the latter through a 1,5-H transfer rearrangement mechanism. Evidences of the radical nature of the reactions mechanism were provided by ESR spectroscopy, furthermore the same technique, allowed to discover that the reaction of azides with indium trichloride and other group XIII Lewis acids, in particular gallium trichloride, gives rise to strongly coloured, persistent paramagnetic species, whose structure is consistent with the radical cation of the head-to-tail dimer of the aniline corresponding to the starting azide.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Bencivenni, Giorgio
Supervisore
Co-supervisore
Dottorato di ricerca
Ciclo
20
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
radicals azides lewis acids indium trichloride gallium trichloride esr spectroscopy
URN:NBN
DOI
10.6092/unibo/amsdottorato/1052
Data di discussione
15 Aprile 2008
URI

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