Selective synthetic routes to sterically hindered unsymmetrical diaryl ketones via arylstannanes
Marcos J Lo Fiego1, Gustavo F Silbestri, Alicia B Chopa
1Instituto de Química del Sur (CONICET-UNS), Departamento de Química, Universidad Nacional del Sur, Avenida Alem 1253, Bahía Blanca, B8000CPB, Argentina.
Abstract:
Bulky arylstannanes and bulky aroyl chlorides are good reaction partners for the synthesis of two-, three-, and even four-ortho-substituted benzophenones, in good to excellent isolated yields (47-91%). Three simple and direct routes, with differential advantages, are proposed: (i) a catalyst-free protocol, in o-dichlorobenzene (ODCB) at 180 °C; (ii) a room temperature protocol, using AlCl(3) (0.5 equiv), in dichloromethane (DCM); and (iii) a solvent-free, indium-promoted procedure. A radical mechanism is proposed for the indium-mediated reactions.
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