Microwave-assisted
efficient synthesis of 2-arylbenzo[b]furans
and
2-ferrocenylbenzo[b]furans from readily prepared
propargylic
alcohols and o-iodophenols
LIANSHENG WU,
XIAOKANG SHI, XIAOYUN XU, FEN LIANG and GUOSHENG HUANG*
State Key Laboratory
of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. of
China
e-mail:
hgs2368@163.com
MS received 14
September 2010; revised 18 May 2011; accepted 27 June 2011
Abstract.
A simple, efficient and expeditious method for synthesis of
2-arylbenzo[b]furans and 2-
ferrocenylbenzo[b]furans
from readily prepared propargylic alcohols, o-iodophenols and silica gel
with the
catalyst of PdCl2(PPh3)2 (2 mol%)/CuI (2mol%)
and microwave-promoted Sonogashira coupling/cyclization
reaction is developed.
The methodology can produce good to excellent yields. In addition, this method
can also
be completed in
one-pot with iodobenzene, 2-methyl-3-butyn-2-ol and 2-iodo-4-methylphenol as
reactants.
Graphical
Abstract. A
simple and efficient method for synthesis of 2-arylbenzo[b]furnas and 2-
ferrocenylbenzo[b]furans has been
developed from the Sonogashira coupling/
cyclization reaction of
propargylic alcohols and o-iodophenols
in the presence
of silica gel and catalytic
amounts of PdCl2(PPh3)2 (2 mol%) and CuI (2
mol%)
under microwave conditions.
Keywords. Benzo[b]furan; o-iodophenol; propargylic alcohols;
microwave irradiation.