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Development of a Mild and Versatile Directed Cycloaddition Approach to Pyridines
Author(s) -
Bachollet Sylvestre P. J. T.,
Vivat Jérôme F.,
Cocker Dean C.,
Adams Harry,
Harrity Joseph P. A.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201403916
Subject(s) - cycloaddition , lewis acids and bases , chemistry , combinatorial chemistry , boron , organic chemistry , catalysis
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 20 min at 40 °C and provide direct access to a broad range of pyridines with complete and predictable regiocontrol. The carbonboron bond can be further functionalised by cross‐coupling allowing further functionality to be introduced after cycloaddition.