2 research outputs found
Aryl Fluorosulfate Trapped Staudinger Reduction
A chemoselective
Staudinger reduction/sulfurÂ(VI) fluoride exchange
cascade has been developed to join two chemical segments through an
aryl sulfamate ester (RNH–SO<sub>2</sub>–OAr) linkage.
Aryl fluorosulfate is exploited in this work as the first tetrahedral
electrophilic trap for the in situ generated iminophosphorane. Ten
examples using azide-containing compounds are presented
Mechanisms and Reactivity Differences for Cycloaddition of Anhydride to Alkyne Catalyzed by Palladium and Nickel Catalysts: Insight from Density Functional Calculations
Mechanisms and reactivity differences
for the cycloaddition of
anhydride to alkyne catalyzed by the palladium and nickel catalysts
have been investigated by extensive density functional theory (DFT)
calculations. The predicted free energy profiles for the Pd- and Ni-catalyzed
reactions have been used to evaluate possible mechanisms for the formation
of different products. Calculations show that the formation of isocoumarin
via the decarbonylative addition of anhydride to alkyne is kinetically
more favorable than the channel to indenone in the Ni-catalyzed reaction.
On the contrary, the preparation of naphthalene through sequential
liberation of CO<sub>2</sub> and CO is kinetically more favorable
than that the formation of indenone in the Pd-catalyzed process. The
bonding differences between Pd–C and Ni–C bonds, arising
from the relativistic effect of late transition metals, play an important
role in regulating their catalytic activity. The calculation results
show good agreement with the experiments