scispace - formally typeset
Search or ask a question

Showing papers by "Edamana Prasad published in 2004"


Journal ArticleDOI
TL;DR: Water has a high affinity for SmI2 (compared to that of the alcohols), and the onset of coordination at relatively low concentrations channels the reaction through a mechanistically distinct pathway.
Abstract: The effects of proton donors (alcohols and water) on the rate of reduction of acetophenone by SmI2 have been examined utilizing stopped-flow spectrophotometric studies. The rate orders with respect to proton source and the kinetic isotope effects were determined as well. The reaction was first-order in phenol, 2,2,2-trifluoroethanol, methanol, and ethanol and zero-order in 2-propanol and 2-methyl-2-propanol when 25 equiv of proton source were used in the reduction. Methanol, ethanol, 2,2,2-trifluoroethanol, and phenol also showed a direct correlation between the pKa of the alcohol and the rate of reduction. Under the same conditions, water had a fractional rate order of 1.4. Further studies showed that water has a rate order of 1 at lower concentrations ( 80 equiv). These results clearly indicate that the nature of the proton donor and its concentration affects the rates of reduction. Water has a high affinity for SmI2 (compared to that of the alco...

108 citations


Journal ArticleDOI
TL;DR: The importance of ligand displacement (exchange) in Sm(II)-HMPA-based reactions and insight into the mechanism of [Sm[N(SiMe(3))(2)] (2)]-HMPA and SmI(2)-HM PA reductions are presented.
Abstract: Addition of HMPA to [Sm{N(SiMe3)2}2] produces a less reactive reductant in contrast to addition of HMPA to SmI2. While the [Sm{N(SiMe3)2}2]−HMPA combination results in a more powerful reductant based on the redox potential, the observed decrease in reactivity is attributed to steric hindrance caused by the nonlabile ligand −N(SiMe3)2 and HMPA around the Sm metal. The importance of ligand displacement (exchange) in Sm(II)−HMPA-based reactions and insight into the mechanism of [Sm{N(SiMe3)2}2]−HMPA and SmI2−HMPA reductions are presented.

43 citations


Journal ArticleDOI
TL;DR: It is revealed that solvation plays an important role in substrate reduction by SmI(2) using methanol as a proton source and reduces in THF, DME, and CH(3)CN provided the anti diastereomer predominantly.

41 citations