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A Click Reaction Enabled by Phosphorus‐Oxygen Bond for Synthesis of Triazoles
Author(s) -
Bal Ankita,
Mal Prasenjit
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202102758
Subject(s) - chemistry , ketone , yield (engineering) , bond cleavage , oxygen , medicinal chemistry , substrate (aquarium) , phosphorus , azide , triple bond , triazole , click chemistry , cleavage (geology) , double bond , polymer chemistry , organic chemistry , catalysis , materials science , oceanography , fracture (geology) , metallurgy , composite material , geology
Synthesis of various N−H triazoles via azidyl radical was achieved using diphenyl phosphoryl azide (DPPA) and internal alkynes containing carbonyl group in wet‐DMSO at 90 °C in excellent yield. Mechanistic investigations revealed that an azidyl radical was generated in the reaction medium. The driving force was probably due to the presence of the C=O group of ester or ketone in conjugation with the triple bond of the substrate. This resulted in cleavage of the phosphorus nitrogen (P−N) bond of DPPA by forming an allenic intermediate. The C=O group of the ester or ketone is a determinant factor that results in triazole as the outcome. The formation of the phosphorus oxygen bond resulted in cleavage of a strong P−N bond (617.1±20.9 kJ mol −1 ) of phosphoryl azidate in an additive free Click reaction of internal alkynes. Overall, good to excellent yield of N 1 ‐H triazole scaffolds were synthesized following the protocol.