Base mediated 1,3-dipolar cycloaddition of α-substituted vinyl phosphonates with diazo compounds for synthesis of 3-pyrazolylphosphonates and 5-pyrazolcarboxylates

Nataliya S Goulioukina; Nikolay N Makukhin; Egor D Shinkarev; Yuri K Grishin; Vitaly A Roznyatovsky; Irina P Beletskaya

doi:10.1039/c6ob01780k

Base mediated 1,3-dipolar cycloaddition of α-substituted vinyl phosphonates with diazo compounds for synthesis of 3-pyrazolylphosphonates and 5-pyrazolcarboxylates

Org Biomol Chem. 2016 Oct 25;14(42):10000-10010. doi: 10.1039/c6ob01780k.

Authors

Nataliya S Goulioukina¹, Nikolay N Makukhin², Egor D Shinkarev², Yuri K Grishin², Vitaly A Roznyatovsky², Irina P Beletskaya¹

Affiliations

¹ Department of Chemistry, Moscow State University, Leninskie Gory, GSP-1, 119991 Moscow, Russian Federation. [email protected] and Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Pr. 31, 119071 Moscow, Russian Federation.
² Department of Chemistry, Moscow State University, Leninskie Gory, GSP-1, 119991 Moscow, Russian Federation. [email protected].

PMID: 27722648
DOI: 10.1039/c6ob01780k

Abstract

5-Aryl-substituted pyrazol-3-ylphosphonates have been conveniently synthesized by 1,3-dipolar cycloaddition of 1-formamidovinylphosphonates and aryldiazomethanes under K₂CO₃/MeOH conditions at room temperature. These pyrazoles are formed in one pot via spontaneous elimination of formamide. Basic conditions prevent competitive formation of cyclopropylphosphonates. 3-Aryl substituted pyrazol-5-carboxylates can be synthesized by the same methodology from 1-arylvinylphosphonates and ethyl diazoacetate, although a stronger base NaH is necessary to ensure the success of the aromatization stage with the elimination of the diethoxylphosphoryl moiety.