Download PDF
Synfacts 2012; 8(1): 0103
DOI: 10.1055/s-0031-1289491
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

One-Pot Tandem Reactions with a Bifunctional Solid Catalyst

Contributor(s):
Yasuhiro Uozumi
,
Yoichi M. A. Yamada
,
Heeyoel Baek
Shiju NR, * Alberts AH, Khalid S, Brown DR, Rothenberg G. * University of Amsterdam, The Netherlands; University of Huddersfield, UK and Brookhaven National Laboratory, Upton, USA
Mesoporous Silica with Site-Isolated Amine and Phosphotungstic Acid Groups: A Solid Catalyst with Tunable Antagonistic Functions for One-Pot Tandem Reactions.

Angew. Chem. Int. Ed. 2011;
50: 9615-9619
CrossrefGoogle Scholar
Further Information

Publication History

Publication Date:
19 December 2011 (online)

 
 PDF Download Permissions and Reprints

Key words

bifunctional acid–base catalysis - one-pot synthesis - mesoporous silica - phosphotungstic acid

Significance

A mesoporous silica catalyst 3 bearing both Brønsted base and acid groups was prepared by immobilization of 3-aminopropyltriethoxysilane [(EtO)3Si(CH2)3NH2] and phosphotungstic acid (H3PW12O40) to a mesoporous silica. Catalyst 3 drove the tandem deacetalization–Henry reaction and deacetalization–Knoevenagel reaction of 4 with nitromethane and malononitrile to give trans-1-nitro-2-phenylethylene 5 and benzylidene malononitrile 6 in 92% and 91% yield, respectively.


#

Comment

The acid/base properties were controlled by the ratio and surface concentration of an amino group and phosphotungstate. Catalyst 3 was characterized by XANES (X-ray absorption near-edge structure spectrum), BET, BJH, 31P NMR, 29Si and 13C CP-MAS NMR spectroscopy and GC-MS. Catalyst 3 was recovered by filtration and reused several times without significant loss of catalytic activity (4th use: 5 in 90% isolated yield, 6 in 91% isolated yield).


#
#


   Permissions and Reprints