INVESTIGADORES
CAMINOS Daniel Alberto
congresos y reuniones científicas
Título:
HOW IS MICROWAVE IRRADIATION INVOLVED IN THE SRN1 INITIATION?
Autor/es:
DANIEL A. CAMINOS; ALEXIS D. GARRO; SILVIA M. SORIA CASTRO; ALICIA B. PEÑÉÑORY
Lugar:
Carlos Paz
Reunión:
Conferencia; CLAFQO-13 13a Conferencia Latinoamericana de Físico-Química Orgánica 13th Latin American Conference on Physical Organic Chemistry; 2015
Institución organizadora:
UNC-CONICET.SAIQO-AAIFQ
Resumen:
Microwave heating devices combined with process that
involves an electron-transfer (ET) step to generate radical anions and radicals
to achieve new C-C bonds, such as SRN1, are attractive in
pharmaceutical and fine chemistry offering a faster and safer synthetic
methodology than conventional procedures.1
Recently we report the use of microwave irradiation
for the formation of new C-C bond in the a-arylation
of aromatic ketones and acetamides by the SRN1 mechanism.2
The microwave-induced reaction showed many advantages such as simplicity,
shorter times, broad substituents compatibility and a better performance in the
heterocyclic synthesis as compared to photoinduced reactions.
The aim of the present work has been to explore the reaction
mechanism under microwave irradiation and its role in the reaction. With this purpose
we investigate the coupling reaction between acetophenone enolate anion and PhI
at different microwave irradiation conditions.
The model coupling reaction is accelerated by
microwave irradiation and this increase in reaction rate is only ascribed to
thermal effects. The coupling reaction
gave the substitution product 1,2-di-phenylethanone in a 50 % yield when
microwave irradiation allowed to reach a reaction temperature range of 70-120 °C,
independently of the microwave pulse. The presence of ionic and dipolar species are not involved in the
initiation process as molecular radiators. The excess of tBuOK
in the reaction medium also acts as electron donor helping to generate
radicals.