940934-41-8Relevant academic research and scientific papers
Palladium-catalyzed nucleophilic substitution of diarylmethyl carbonates with malonate carbanions
Kuwano, Ryoichi,Kusano, Hiroki
, p. 528 - 529 (2007)
The nucleophilic substitution of diarylmethyl carbonates with malonate carbanions proceeded in the presence of [Pd(π-C3H 5)(cod)]BF4-Cy-Xantphos, giving the desired (diarylmethyl)malonates in up to 90% yield. The yield was extremely affected by choice of the phosphine ligand. Copyright
Nucleofugality of phenyl and methyl carbonates
Denegri, Bernard,Kronja, Olga
, p. 8427 - 8433 (2008/03/12)
(Chemical Equation Presented) A series of X,Y-substituted benzhydryl phenyl carbonates 1 and X,Y-substituted benzhydryl methyl carbonates 2 were subjected to solvolysis in different methanol/water, ethanol/water, and acetone/water mixtures at 25°C. The LFER equation, log k = sf(Ef + Nf), was used to derive the nucleofuge-specific parameters (N f and sf) for phenyl carbonate (1LG) and methyl carbonate (2LG) leaving groups in a given solvent in SN1 type reaction. Kinetic measurements showed that phenyl carbonates solvolyze one order of magnitude faster than methyl carbonates. Optimized geometries of 1LG and 2LG at B3LYP/6-311G(d,p), B3LYP/6-311++G(d,p), and MP2(full)/6-311++G(d,p) levels revealed that negative charge delocalization in carbonate anions to all three oxygen atoms occurs due to negative hyperconjugation. Phenyl carbonate (1LG) is a better leaving group (Nf = -0.84 ± 0.07 in 80% v/v aq EtOH) than methyl carbonate 2LG (Nf = -1.84 ± 0.07 in 80% v/v aq EtOH) because of more pronounced negative hyperconjugation, which is characterized with a more elongated RO-C bond and more increased RO-C-CO angle in 1LG than in 2LG. Calculated affinities of benzhydryl cation toward methyl and phenyl carbonate anions (ΔΔEaff = 11.7 kcal/mol at the B3LYP/6-311++G(d,p) level and ΔΔEaff = 2.7 kcal/mol at the PCM-B3LYP/6-311++G(d,p) level in methanol, respectively) showed that 1LG is more stabilized than 2LG, which is in accordance with greater solvolytic reactivity of 1 than 2.
