Photoisomerization of Vinylboranes with an Organocatalyst
Vinylboranes can quickly isomerize in the presence of thioxanthone [T2351] as a photocatalyst to give the corresponding stereoisomer in high yields upon irradiation under visible light. In this reaction, both the borane moiety and carbonyl group are necessary and it is found that the isomerization seldom proceeds in the absence of either group, thus indicating an olefin-selective isomerization. This reaction has the advantage of wide substrate versatility except for the necessary presence of a borane moiety and a carbonyl group.
Oxime-Derived Palladacycles as Versatile Catalysts in Cross-Coupling Reactions
Metallacycles are derivatives of carbocyclic compounds wherein a metal has replaced at least one carbon center. These have garnered attention due to their high catalytic reactivity. Metallacycles are derivatives of carbocyclic compounds wherein a metal has replaced at least one carbon center. These have garnered attention due to their high catalytic reactivity. Najera Catalyst I [D3806] and Najera Catalyst II [D3807] are among the metallacycles that have been used as catalysts for carbon-carbon bond formation. D3806 and D3807 are thermally stable and not sensitive to air or moisture, and exhibit high catalytic activity in organic as well as in aqueous solvents. Applications of the above two catalysts to various cross-coupling reactions, such as the Sonogashira, Hiyama, Suzuki-Miyaura and Heck-type reactions has already been reported.
The Pummerer rearrangement is a well-established rearrangement of a sulfoxide to an α-acyloxy-thioether, which has an array of useful synthetic implications. In the presence of an anhydride like acetic anhydride, the sulfoxide-O is acylated, which has an array of useful synthetic implications. In presence of an acid anhydride, the sulfoxide-O is acylated, which upon rapid elimination generates a thial intermediate. The thial intermediate is further acylated resulting in the desired α-acyloxy-thioether product. However, the thial can be attacked by a wide array of nucleophiles and therefore has noted applications in total synthesis.
Sialylated N-Glycan Series, Functionally-modified at the Reducing End
Sialylated N-glycan are a typical human-type polysaccharide that is suggested to be strongly correlated with various physiological phenomena, such as viral infection and anti-inflammatory activity, through endogenous immune-receptors. TCI has a lineup of sialylated N-glycan reducing end modification products useful for various applications like click chemistry and high sensitivity requiring analytical work.