Synthesis of indazoles by the [3+2] cycloaddition of diazo compounds with arynes and subsequent acyl migration.
The [3+2] cycloaddition of a variety of diazo compounds with o-(trimethylsilyl)aryl triflates in the presence of CsF or TBAF at room temperature provides a very direct, efficient approach to a wide range of potentially biologically and pharmaceutically interesting substituted indazoles in good to excellent yields under mild reaction conditions. Simple diazomethane derivatives afford N-unsubstituted indazoles or 1-arylated indazoles, depending upon the stoichiometry of the reagents and the reaction conditions, while dicarbonyl-containing diazo compounds undergo carbonyl migration to afford 1-acyl or 1-alkoxycarbonyl indazoles selectively.
Liu
Zhijian
Z
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Shi
Feng
F
Martinez
Pablo D G
PD
Raminelli
Cristiano
C
Larock
Richard C
RC
D000480:Alkynes / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D003500:Cyclization; D007191:Indazoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D000480:Alkynes; D001391:Azo Compounds; D007191:Indazoles