Issue 11, 2018

Gold-catalyzed [4+3]- and [4+2]-annulations of 3-en-1-ynamides with isoxazoles via novel 6π-electrocyclizations of 3-azahepta trienyl cations

Abstract

New gold-catalyzed [4+3]-annulations of 3-en-1-ynamides with isoxazoles afford 4H-azepines efficiently; this process involves 6π electrocyclizations of gold-stabilized 3-azaheptatrienyl cations. In the presence of Zn(OTf)2, the resulting 4H-azepines undergo skeletal rearrangement to furnish substituted pyridine derivatives. We subsequently develop new catalytic [4+2]-annulations between the same 3-en-1-ynamides and isoxazoles to deliver substituted pyridine products using Au(I)/Zn(II) catalysts. This work reports the first success of the 6π electrocyclizations of heptatrienyl cations that are unprecedented in literature reports.

Graphical abstract: Gold-catalyzed [4+3]- and [4+2]-annulations of 3-en-1-ynamides with isoxazoles via novel 6π-electrocyclizations of 3-azahepta trienyl cations

Supplementary files

Article information

Article type
Edge Article
Submitted
15 jan. 2018
Accepted
18 feb. 2018
First published
19 feb. 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2018,9, 2991-2995

Gold-catalyzed [4+3]- and [4+2]-annulations of 3-en-1-ynamides with isoxazoles via novel 6π-electrocyclizations of 3-azahepta trienyl cations

S. S. Giri and R. Liu, Chem. Sci., 2018, 9, 2991 DOI: 10.1039/C8SC00232K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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