ORGANIC
LETTERS
2011
Vol. 13, No. 24
6402–6405
An Efficient Route to
Tetrahydroindeno[2,1-b]pyrroles via a
Base-Promoted Reaction of
(E)-2-Alkynylphenylchalcone with
2-Isocyanoacetate
Danqing Zheng,† Shaoyu Li,† Yong Luo,† and Jie Wu*,†,‡
Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433,
China, and State Key Laboratory of Organometallic Chemistry, Shanghai Institute of
Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
Received October 9, 2011
ABSTRACT
A base-promoted cascade reaction of (E)-2-alkynylphenylchalcone with 2-isocyanoacetate provides a novel and efficient route for the synthesis of
tetrahydroindeno[2,1-b]pyrroles. The reaction proceeds smoothly in air under mild conditions with high efficiency.
Currently, diversity-oriented synthesis has been used as
an efficient strategy for the generation of natural product-
likecompoundstoaddress the challengeposedby chemical
genetics.1 Thus, natural product-like compounds with
privilegedscaffolds which are knowntobe pronetodisplay
different biological activities are in great demand. Among
the approaches applied for the generation of these
compounds, the cascade reaction has been demonstrated
as an ideal method.2,3 Recently, we have constructed a
small library of indene compounds with structural diver-
sity via cascade reactions.4 The compounds (Figure 1)
include indene-incorporated quinolines A,4a,c chromenes
B,4b and seven-membered ring lactams C.4d The subse-
quent biological assay disclosed several hits for inhibition
of HCT-116. In order to find more active compounds, we
need to explore efficient methods for facile assembly of
otherindene-incorporated heterocycles. Herein, wewishto
† Fudan University.
‡ Chinese Academy of Sciences.
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r
10.1021/ol202708f
Published on Web 11/11/2011
2011 American Chemical Society