Development of a mild and versatile directed cycloaddition approach to pyridines.
Chemistry
; 20(40): 12889-93, 2014 Sep 26.
Article
em En
| MEDLINE
| ID: mdl-25145488
The aza-Diels-Alder cycloaddition of 1,2,4-triazines with alkynes offers a rapid and convenient method for the synthesis of highly substituted pyridines, but often requires harsh conditions and long reaction times. The present study offers a solution to these limitations by use of a temporary tether established by a Lewis acid-base complexation of in situ generated alkynylboranes and triazines bearing a Lewis basic donor. The cycloaddition reactions take place within 20â
min at 40 °C and provide direct access to a broad range of pyridines with complete and predictable regiocontrol. The carbonboron bond can be further functionalised by cross-coupling allowing further functionality to be introduced after cycloaddition.
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MEDLINE
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En
Ano de publicação:
2014
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Article