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An Efficient, Facile, and General Synthesis of 1 H ‐Indazoles by 1,3‐Dipolar Cycloaddition of Arynes with Diazomethane Derivatives
Author(s) -
Jin Tienan,
Yamamoto Yoshinori
Publication year - 2007
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200700101
Subject(s) - diazomethane , aryne , cycloaddition , indazole , chemistry , trifluoromethanesulfonate , aryl , medicinal chemistry , combinatorial chemistry , organic chemistry , stereochemistry , catalysis , alkyl
Take your pick : Both N‐unsubstituted and 1‐aryl 1 H ‐indazoles are available in good to high yields through the [3+2] cycloaddition of benzynes derived from o ‐silylaryl triflates with diazomethane derivatives (see scheme). In the presence of KF/[18]crown‐6, the N‐unsubstituted 1 H ‐indazole is formed, whereas the 1‐arylated product is obtained regioselectively with CsF and an excess of the triflate.