Regioselective cycloaddition of trifluorodiazoethane with electron-deficient allenic esters and ketones: access to CF3-substituted pyrazolines and pyrazoles

Fa-Guang Zhang; Yi Wei; Yu-Ping Yi; Jing Nie; Jun-An Ma

doi:10.1021/ol501249h

Regioselective cycloaddition of trifluorodiazoethane with electron-deficient allenic esters and ketones: access to CF3-substituted pyrazolines and pyrazoles

Org Lett. 2014 Jun 6;16(11):3122-5. doi: 10.1021/ol501249h. Epub 2014 May 21.

Authors

Fa-Guang Zhang¹, Yi Wei, Yu-Ping Yi, Jing Nie, Jun-An Ma

Affiliation

¹ Department of Chemistry, Key Laboratory of Systems Bioengineering (the Ministry of Education), Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, P. R. China.

PMID: 24850209
DOI: 10.1021/ol501249h

Abstract

A highly regioselective cycloaddition procedure of electron-deficient allenes with trifluorodiazoethane (CF3CHN2) is described. In absence of bases, the reaction proceeded smoothly to give 5-(trifluoromethyl)pyrazolines, whereas the utility of Et3N led to the formation of 3-(trifluoromethyl)pyrazoles.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Azo Compounds / chemistry*
Cycloaddition Reaction
Electrons
Esters
Hydrocarbons, Fluorinated / chemical synthesis*
Hydrocarbons, Fluorinated / chemistry
Ketones / chemistry*
Molecular Structure
Pyrazoles / chemical synthesis*
Pyrazoles / chemistry
Stereoisomerism

Substances

Azo Compounds
Esters
Hydrocarbons, Fluorinated
Ketones
Pyrazoles