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.
Fig. 1: Mechanistic pathway for the formation of [4a] by Heck cyclization protocol
Pages: 121-129 | 1343 Views 10 Downloads
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.