International Journal of Chemical Studies
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P-ISSN: 2349-8528, E-ISSN: 2321-4902   |   Impact Factor: GIF: 0.565

International Journal of Chemical Studies

Vol. 1, Issue 4 (2013)
Regioselective synthesis of a series of bis-biaryl coupled heterocycles: The superiority of Heck protocol compared to Bu3SnH mediated radical cyclization


Author(s): Pradipta Kumar Basu, Amrita Ghosh

Abstract: In this work two new effective methodologies involving Bu3SnH annulated radical cyclization and Heck protocol have been emphasized for the preparation of substituted dihydrobenzo-isochromeno[4,3-h] chromene derivatives[4(a–f)]. At first, 2,3-dihydroxy naphthalene[1a] or 1,5-dihydroxy naphthalene[1b]  or 1,6-dihydroxy naphthalene[1c] was reacted with 2-bromobenzyl bromide[2a] or 2-bromo-5-methoxy benzyl bromide[2b] in presence of acetone and potassium carbonate under reflux and thus generated several bis (2-bromobenzyloxy)naphthalene derivatives[3(a–f)]. The superiority of the Heck protocol in comparison to the radical cyclization strategy has been highlighted for the regioselective synthesis of bis-biaryl coupled heterocycles[4(a–f)].The Heck method is relatively simple, straightforward, and highly regioselective and high yielding too.

Mechanistic pathway for the formation of [4a] by Heck cyclization protocol
Fig. 1: Mechanistic pathway for the formation of [4a] by Heck cyclization protocol

Pages: 121-129  |  1090 Views  10 Downloads

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How to cite this article:
Pradipta Kumar Basu, Amrita Ghosh. Regioselective synthesis of a series of bis-biaryl coupled heterocycles: The superiority of Heck protocol compared to Bu3SnH mediated radical cyclization. Int J Chem Stud 2013;1(4):121-129.
International Journal of Chemical Studies