Pyrrole-2,3-quinodimethane analogues in the synthesis of indoles. Part 2.1 Synthesis and diels-alder reactions of 1,6-dihydropyrano[4,3-b]pyrrol-6(1H)-ones

doi:10.1016/S0040-4020(01)87212-4

Tetrahedron

Volume 49, Issue 33, 13 August 1993, Pages 7353-7372

Dedicated to Professor Alan R. Katritzky, FRS on the occasion of his 65th birthday

https://doi.org/10.1016/S0040-4020(01)87212-4 Get rights and content

Abstract

The pyrano[4,3-b]pyrrol-6-ones 7-9, 12 and 13 are stable cyclic analogues of pyrole-2,3-quinodimethane, and undergo Diels-Alder reaction with a range of alkynes to give, after loss of carbon dioxide, indoles.

A new route to indoles involving the Diels-Alder reaction of 1,6-dihydropyrano[4,3-b]pyrrol-5-ones with alkynes is described.

References (12)

P.M. Jackson et al.
Tetrahedron
(1992)
C.J. Moody et al.
J. Chem. Soc., Perkin Trans. 1
(1990)
P.M. Jackson et al.
J. Chem. Soc., Perkin Trans. 1
(1990)
P.M. Jackson et al.
J. Chem. Soc., Perkin Trans. 1
(1990)
H.J. Anderson et al.
Can. J. Chem.
(1980)
B.J. Demopoulos et al.
Can. J. Chem.
(1983)

There are more references available in the full text version of this article.

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Pyrrole-2,3-quinodimethane analogues in the synthesis of indoles. Part 2.1 Synthesis and diels-alder reactions of 1,6-dihydropyrano[4,3-b]pyrrol-6(1H)-ones

Abstract

Tetrahedron

J. Chem. Soc., Perkin Trans. 1

J. Chem. Soc., Perkin Trans. 1

J. Chem. Soc., Perkin Trans. 1

Can. J. Chem.

Can. J. Chem.