Expanding available pyrazole substitution patterns by sydnone cycloaddition reactions
作者:A.W. Brown、J.P.A. Harrity
DOI:10.1016/j.tet.2017.04.049
日期:2017.6
We report the use of alkynylsilanes for the regiocontrolled synthesis of pyrazoles from functionalised sydnones. The strategies outlined herein allow a range of pyrazoles to be accessed with substitution patterns that are otherwise not directly obtained with high selectivity by alkyne cycloadditions. Moreover, this study serendipitously highlighted a simple and convenient procedure for the synthesis
Synthesis of aminopyrazoles from sydnones and ynamides
作者:T. Wezeman、J. Comas-Barceló、M. Nieger、J. P. A. Harrity、S. Bräse
DOI:10.1039/c6ob02518h
日期:——
Aminopyrazoles are prepared from readily accessible sydnones and sulfonyl ynamides using either a copper-mediated sydnone alkyne cycloaddition (CuSAC) or in situ generated strained cyclic ynamides.
Synthesis of [<sup>18</sup>F]Fluoroarenes by Nucleophilic Radiofluorination of<i>N</i>-Arylsydnones
作者:Maruthi Kumar Narayanam、Gaoyuan Ma、Pier Alexandre Champagne、Kendall N. Houk、Jennifer M. Murphy
DOI:10.1002/anie.201707274
日期:2017.10.9
Easy to handle: A practical radiofluorination of anilines with [18F]fluoride is achieved via N-arylsydnone intermediates. This method displays broad functional group tolerance, is compatible to automation on a commercial radiosynthesis module and can facilitate rapid 18F-labeling of peptides.
Room-Temperature Direct Alkenylation of 3-Arylsydnones
作者:Yiwen Yang、Chunxiang Kuang
DOI:10.1002/ejoc.201403211
日期:2014.12
A new efficient method for the directalkenylation of 3-arylsydnones by palladium-catalyzed C–H functionalization was developed. The reaction proceeded smoothly at room temperature and delivered the product in yields up to 83 %.
Exploiting Synergistic Catalysis for an Ambient Temperature Photocycloaddition to Pyrazoles
作者:Christopher P. Lakeland、David W. Watson、Joseph P. A. Harrity
DOI:10.1002/chem.201904210
日期:2020.1.2
Sydnone-based cycloaddition reactions are a versatile platform for pyrazole synthesis, however they operate under harsh conditions (high temperature and long reaction times). Herein we report a strategy that addresses this limitation utilizing the synergistic combination of organocatalysis and visible-light photocatalysis. This new approach proceeds under ambient conditions and with excellent levels