256229-09-1Relevant articles and documents
Chemoselective Nucleophilic Functionalizations of Aromatic Aldehydes and Acetals via Pyridinium Salt Intermediates
Kawajiri, Takahiro,Kato, Maho,Nakata, Hiroki,Goto, Ryota,Aibara, Shin-Yo,Ohta, Reiya,Fujioka, Hiromichi,Sajiki, Hironao,Sawama, Yoshinari
, p. 3853 - 3870 (2019/03/07)
The development of a novel chemoselective functionalization can diversify the strategy for synthesizing the target molecules. The perfect chemoselectivity between aromatic and aliphatic aldehydes is difficult to achieve by the previous methods. The aromatic aldehyde-selective nucleophilic addition in the presence of aliphatic aldehydes was newly accomplished. Namely, the aromatic aldehyde-selective nucleophilic addition using arenes and allyl silanes proceeded in the presence of trialkylsilyl triflate and 2,2′-bipyridyl, while the aliphatic aldehydes completely remained unchanged. The reactive pyridinium-type salt intermediate derived from an aromatic aldehyde chemoselectively underwent the nucleophilic substitution. Moreover, the aromatic acetals as the protected aldehydes could be directly transformed into similar pyridinium salt intermediates, which reacted with various nucleophiles coexisting with the aliphatic aldehydes.
Almond oxynitrilase-catalyzed transformation of aldehydes is strongly influenced by naphthyl and alkoxy substituents
Roda, Gabriella,Riva, Sergio,Danieli, Bruno
, p. 3939 - 3949 (2007/10/03)
Different α- and β-substituted aldehydes have been submitted to the catalytic action of almond oxynitrilase (PaHNL), in order to explore the influence of a stereocenter already present in the substrate on the selectivity of this enzyme. The results indicate that naphthyl and alkoxy substituents in the α- and also in the β-position to the aldehyde group significantly influence the stereochemical outcome of the PaHNL-catalyzed transformation.
