Chiral pyrrolidine quaternary derivatives
as organocatalysts for asymmetric Michael additions
Received: 18 December 2011 / Accepted: 28 December 2011 / Published online: 7 January 2012
Ó Springer Science+Business Media B.V. 2012
Abstract A series of chiral pyrrolidine quaternary derivatives were designed and
synthesized. It was found that these derivatives are highly efﬁcient organocatalysts
for the asymmetric Michael addition reactions of aldehydes and ketones to nitro-
oleﬁns with high yields (up to 96%), high enantioselectivities (up to 99% ee), and
high diastereoselectivities (up to 97:3 dr). Furthermore, catalyst 7a could be recy-
cled without remarkable loss of catalytic activity and stereoselectivity.
Keywords Chiral pyrrolidine quaternary derivatives Á Asymmetric Michael
additions Á Organocatalysts Á Nitrostyrenes
In recent years, the asymmetric Michael addition reactions have draw much attention
because it is one of the most important carbon–carbon bond-forming reactions in
organic chemistry [1–6]. The organocatalytic asymmetric Michael addition of ketone
to nitrooleﬁns was ﬁrst reported by List  and Barbas , independently. Since then,
there has been a tremendous increase in research activities concerning this area, and
many effective organocatalysts have been widely developed [9–17].
Among the various organocatalysts, proline and its derivatives have been
demonstrated to make up a successful class of organocatalysts in enamine
chemistry. Some of them have been developed for asymmetric Michael reactions
of ketones to nitrooleﬁns with high enantioselectivity and diastereoselectivity.
Unfortunately, these organocatalysts have some drawbacks. One major disadvan-
tage is that they cannot be easily recycled .
H. Sun Á G. Wang Á X. Yan (&) Á L. Chen
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
Res Chem Intermed (2012) 38:1501–1509