Oligosubstituted Pyrroles Directly from Substituted Methyl Isocyanides and Acetylenes
The formal cycloaddition of α‐metallated methyl isocyanides 1 onto the triple bond of electron‐deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25–97 % yield) are reported along with an optimiz...
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Published in | Chemistry : a European journal Vol. 15; no. 1; pp. 227 - 236 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
WILEY‐VCH Verlag
01.01.2009
Wiley |
Subjects | |
Online Access | Get full text |
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Summary: | The formal cycloaddition of α‐metallated methyl isocyanides 1 onto the triple bond of electron‐deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25–97 % yield) are reported along with an optimization of the reaction conditions and a rationalization of the mechanism. In addition, a related newly developed CuI‐mediated synthesis of 2,3‐disubstituted pyrroles by the reaction of copper acetylides derived from unactivated terminal alkynes with substituted methyl isocyanides is described (11 examples, 5–88 %yield).
Convenient pyrrole syntheses: Two new protocols have been developed for one‐pot, one‐step formal [3+2] cycloadditions of substituted methyl isocyanides onto the triple bond of either acceptor‐activated internal or non‐activated terminal acetylenes leading to 2,3,4‐trisubstituted and 2,3‐disubstituted pyrroles, respectively (see scheme). |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0947-6539 1521-3765 |
DOI: | 10.1002/chem.200801395 |