Development of Synthetic methodology
Basker Rajagopal
Our research group’s primary motive in synthetic organic chemistry is the development of new methodologies using copper and rhodium catalyst denitrogenative reactions of N-sulfonyl-1,2,3-triazoles. These N-sulfonyl-1,2,3-triazoles synthesized by the conventional Click chemistry using copper catalyzed azide alkyne cycloaddition reactions (CuAAC) are found to be a versatile surrogate for the α-carbonyl diazo compounds. By using appropriate metal catalyst and reaction conditions they can be converted into many valuable heterocycles via reactive intermediates. While the usage of copper catalysts involves N-sulfonyl ketenimine intermediate, the rhodium (II) catalysts generate aza vinyl rhodium carbenoid intermediates. In recent years, we disclosed interesting methods to synthesize important N-heterocycles.
Synthesis of Dihydropyrmidinones:
J. Org. Chem. 2014, 79, 1254−1264
By exploiting the copper catalyst ketenimine chemistry, a simple and convenient method to prepare dihydropyrimidinone analogues from the corresponding N-propargylamides was developed. This strategy was also applied into the synthesis of β-amino acids analogues from the equivalent α-amino acids.
Synthesis of Indolylimines:
Org. Lett. 2014, 16, 3752−3755
An efficient Cu/Rh-catalyzed method was developed for the synthesis of 3-indolylimines from N-propargylanilines through Rh(II)-catalyzed denitrogenative annulation of N-sulfonyl-1,2,3-triazoles. This one-pot method enables the direct incorporation of an imine, aldehyde, or amine group into an indole system starting from simple alkyne. A variety of substituted 3-indolylimines, indole-3-carboxaldehydes, and 3-Indolylmethanamines are synthesized efficiently.
Synthesis of dihydrobenzofurans: