Journal
JOURNAL OF ORGANIC CHEMISTRY
Volume 82, Issue 1, Pages 256-268Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.joc.6b02389
Keywords
-
Categories
Funding
- Russian Foundation for Basic Research [16-03-00596, 16-33-60130, 16-33-00651]
- St. Petersburg State University [12.38.239.2014, 12.38.217.2015]
Ask authors/readers for more resources
4-Aminopyrrole-3-carboxylates and pyrazine-2-carboxylates were synthesized from 5-alkoxyisoxazoles and 1-sulfonyl-1,2,3-triazoles by tuning the Rh(II) catalyst and the reaction conditions. The reaction in chloroform at 100 degrees C under Rh-2(OAc)(4) catalysis provides 4-aminopyrrole-3-carboxylates in good yields. The use of Rh-2(Piv)(4) in refluxing toluene results in the formation of 1,2-dihydropyrazine-2-carboxylates as the main products, which can be converted by a one-pot procedure to pyrazine-2-carboxylates by heating with catalytic amounts of TsOH. According to the NMR and DFT investigations of the reaction mechanism, pyrroles and dihydropyrazines are formed, respectively, via 1,5- and 1,6-cyclization of common (5Z)-1,4-diazahexa-1,3,5-triene intermediates. The influence of the nature of the catalyst on the product distribution is rationalized in terms of the Rh-catalyzed isomerization of a pyrrolin-2-ylium-3-aminide zwitterion, the primary product of 1,4-diazahexatriene 1,5-cyclization.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available