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Synthesis 2002(8): 1110-1114
DOI: 10.1055/s-2002-31970
PAPER
© Georg Thieme Verlag Stuttgart · New York

A Practical Indium Tribromide Catalysed Addition of Indoles to Nitroalkenes in Aqueous Media

Marco Bandini*, Paolo Melchiorre, Alfonso Melloni, Achille Umani-Ronchi*
Dipartimento di Chimica ‘G. Ciamician’, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy
Fax: +39(51)2099456; e-Mail: bandini@ciam.unibo.it, umani@ciam.unibo.it;
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Publication History

Received 27 March 2002
Publication Date:
03 June 2002 (online)

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Abstract

The 1,4-conjugate addition of indoles to nitroalkenes was efficiently carried out in aqueous media using a catalytic amount of indium tribromide (5 mol%). The reusability of the indium tribromide was tested by performing consecutive cycles with the same catalyst.

Key words

alkaloids - catalysis - indium - indoles - Michael additions

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9

Other common Lewis acids were found to be less effective in term of chemical yields and reaction times (i.e. AlCl3, 68% yield, 24 h).