A Brønsted Acid Catalyst for the Enantioselective Protonation Reaction
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1021/ja8041542
日期:2008.7.1
A highly reactive and robust chiral Brønstedacidcatalyst, chiral N-triflyl thiophosphoramide, was developed. The first metal-free Brønstedacid catalyzed enantioselective protonation reaction of silyl enol ethers was demonstrated using this chiral Brønstedacidcatalyst. The catalyst loading could be reduced to 0.05 mol % without any deleterious effect on the enantioselectivity.
Development of a new Lewis base-tolerant chiral LBA and its application to catalytic asymmetric protonation reaction
作者:Cheol Hong Cheon、Tatsushi Imahori、Hisashi Yamamoto
DOI:10.1039/c0cc02492a
日期:——
A new Lewis base-tolerant LBA (LewisAcidAssistedBronstedAcid) derived from La(OTf)(3) and (S)-HOP has been developed as a new chiralBronstedacid. This acid has been successfully applied as a catalyst to asymmetric protonation reactions of silylenolethers of 2-substituted cyclic ketones.
Macrocyclic pyrimidine compounds, compositions comprising such compounds, methods for making the compounds, and methods of treating and preventing the progression of diseases, conditions, and disorders using such compounds and compositions are described herein.
Caubere,P.; Mourad,M.S., Bulletin de la Societe Chimique de France, 1974, p. 1415 - 1420
作者:Caubere,P.、Mourad,M.S.
DOI:——
日期:——
Hydrogen‐Bond‐Modulated Nucleofugality of Se
<sup>III</sup>
Species to Enable Photoredox‐Catalytic Semipinacol Manifolds
作者:Sooyoung Park、Amit K. Dutta、Carina Allacher、Anton Abramov、Philipp Dullinger、Katerina Kuzmanoska、Daniela Fritsch、Patrick Hitzfeld、Dominik Horinek、Julia Rehbein、Patrick Nuernberger、Ruth M. Gschwind、Alexander Breder
DOI:10.1002/anie.202208611
日期:2022.12.5
AbstractChemical bond activations mediated by H‐bond interactions involving highly electronegative elements such as nitrogen and oxygen are powerful tactics in modern catalysis research. On the contrary, kindred catalytic regimes in which heavier, less electronegative elements such as selenium engage in H‐bond interactions to co‐activate C−Se σ‐bonds under oxidative conditions are elusive. Traditional strategies to enhance the nucleofugality of selenium residues predicate on the oxidative addition of electrophiles onto SeII‐centers, which entails the elimination of the resulting SeIV moieties. Catalytic procedures in which SeIV nucleofuges are substituted rather than eliminated are very rare and, so far, not applicable to carbon‐carbon bond formations. In this study, we introduce an unprecedented combination of O−H⋅⋅⋅Se H‐bond interactions and single electron oxidation to catalytically generate SeIII nucleofuges that allow for the formation of new C−C σ‐bonds by means of a type I semipinacol process in high yields and excellent selectivity.