Conversion of carbon dioxide into 2-oxazolidinones and 2(3H)-oxazolones catalyzed by 2,2′,2″-terpyridine

Article abstract of DOI:10.1016/j.tet.2016.01.015

The catalytic activation of pyridines as organocatalysts in the three-component cycloaddition of CO₂, propargyl alcohol and primary amine was investigated, and 2,2′,2″-Terpyridine was found to be the efficient organocatalyst to afford 4-methylene-2-oxazolidinones or 2(3H)-oxazolones in good to high yields. 2,2′,2″-Terpyridine also showed high catalytic activity in the coupling reaction of CO₂ with aziridines bearing either electron-donating or electron-withdrawing N-substituents to give substituted 2-oxazolidinones in high yields.

Full text of DOI:10.1016/j.tet.2016.01.015

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Accepted Manuscript
Conversion of carbon dioxide into 2-oxazolidinones and 2(3H)-oxazolones catalyzed
by 2,2',2'-terpyridine
Huixin Liu, Ruimao Hua
PII:
S0040-4020(16)30015-1
10.1016/j.tet.2016.01.015
TET 27422
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 18 October 2015
Revised Date: 2 January 2016
Accepted Date: 8 January 2016
Please cite this article as: Liu H, Hua R, Conversion of carbon dioxide into 2-oxazolidinones and 2(3H)-
oxazolones catalyzed by 2,2',2'-terpyridine, Tetrahedron (2016), doi: 10.1016/j.tet.2016.01.015.
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Graphical Abstract
Conversion of carbon dioxide into 2-oxazolidinones and 2(3H)-oxazolones catalyzed by
2,2',2''-terpyridine
1

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Conversion of carbon dioxide into 2-oxazolidinones and 2(3H)-oxazolones catalyzed by
2,2',2''-terpyridine
Huixin Liu, Ruimao Hua*
Department of Chemistry, Tsinghua University, Beijing 100084, China
Fax: +86-10-62771149
E-mail: ruimao@mail.tsinghua.edu.cn
Abstract:
The catalytic activation of pyridines as organocatalysts in the three-component cycloaddition of
CO2, propargyl alcohol and primary amine was investigated, and 2,2',2''-Terpyridine was found to
be the efficient organocatalyst to afford 4-methylene-2-oxazolidinones or 2(3H)-oxazolones in
good to high yields. 2,2',2''-Terpyridine also showed high catalytic activity in the coupling reaction
of CO2 with aziridines bearing either electron-donating or electron-withdrawing N-substitutents to
give substituted 2-oxazolidinones in high yields.
Key Words: Carbon dioxide; 4-Methylene-2-oxazolidinones; 2-Oxazolidinones; 2(3H)-Oxazolones,
Pyridine; 2,2',2''-Terpyridine
1. Introduction
Substituted 2-oxazolidinones are one of the important five-membered heterocyclic compounds,
which not only show interesting biological and physiological activities,1 but also have been applied
as intermediates in the synthesis of other functional compounds.2 In particular, chiral
2-oxazolidinones have been widely applied as chiral auxiliaries in asymmetric syntheses,3 and
substituted 4-methylene-2-oxazolidinones are the good synthons for the formation of spiro
compounds.4 Owing to the importance of 2-oxazolidinones, a variety of methods were developed
for their selective synthesis.5 Among recent reported synthetic methods, the reaction of CO2 with
propargylamines,6 or the three-component cycloaddition of CO2, propargyl alcohols and primary
1

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amines giving 4-methylene-2-oxazolidinones,7 or the coupling reaction of CO2 with aziridines
affording 2-oxazolidinones8 are the most interesting and promising synthetic methods from the
viewpoint of developing CO2 as carbon source, since the transformation of CO2 into the
value-added organic compounds is a very important and a hot research topic in organic synthetic
chemistry and green chemistry.
Recent years, attempts have been made in our group to develop the efficient catalyst systems
including not only transition metal complexes,9 but also organic compounds10 as catalysts to
transfer CO2 into organic compounds. In continuation of our interest in developing efficient
catalysts in the transformation of CO2 into the value-added organic compounds, we are interested in
the synthesis of 4-methylene-2-oxazolidinones from the three-components cycloaddition of CO2,
propargyl alcohols and primary amines in the presence of pyridine and its derivatives as
7(b)
organocatalysts. Because there are only two papers reporting such transformation by using PBu3
and guanidine7(h) as organocatalysts, and however 2,2',2''-terpyridine was found to be the efficient
organocatalyst in our group in the coupling reaction of CO2 with epoxides giving cyclic
carbonates.10(b)
2. Results and discussion
The three-component cycloaddition of CO2, 2-phenyl-3-butyn-2-ol (1a) and n-propylamine (2a)
was performed in an autoclave with stirring under different conditions to examine the catalytic
activity of pyridines and to find out the optimal conditions. A mixture of 1a, 2a (2.0 equiv) and
pyridine or its derivatives (0.05 equiv) was placed in a 25-mL of autoclave, and CO2 (3.0 MPa of
initial pressure) was pressurized directly to the autoclave under air atmosphere at ambient
temperature, and then the autoclave was heated at 140 oC (oil bath temperature). As summarized in
Table 1, without any catalyst, the expected reaction also took place, and the desired
5-methyl-4-methylene-5-phenyl-3-n-propyloxazolidin-2-one (3a) was formed in 17% GC yield
after 24 h (entry 1), but the use of 5 mol% pyridine as organocatalyst could greatly increase the
yield to 50% (entry 2). The substituted pyridine derivatives at 2- position, such as 2-methylpyridine
2