Scandium trisdodecylsulfate

Sc(() l f) ( is an effective catalyst of the Mukaiyama aldol reaction in both aqueous and non-aqueous media (vide supra). Kobayashi et al. have reported that aqueous aldehydes as well as conventional aliphatic and aromatic aldehydes are directly and efficiently converted into aldols by the scandium catalyst [69]. In the presence of a surfactant, for example sodium dodecylsulfate (SDS) or Triton X-100, the Sc(OTf)3-catalyzed aldol reactions of SEE, KSA, and ketene silyl thioacetals can be performed successfully in water wifhout using any organic solvent (Sclieme 10.23) [72]. They also designed and prepared a new type of Lewis acid catalyst, scandium trisdodecylsulfate (STDS), for use instead of bofh Sc(OTf) and SDS [73]. The Lewis acid-surfactant combined catalyst (LASC) forms stable dispersion systems wifh organic substrates in water and accelerates fhe aldol reactions much more effectively in water fhan in organic solvents. Addition of a Bronsted acid such as HCl to fhe STDS-catalyzed system dramatically increases the reaction rate [74]. 

Lewis acid-surfactant combined catalysts (LASCs) are possible solutions to address this issue. LASCs designed from water-compatible Lewis acids are expected to act as surfactants as well as Lewis acids in water. One example of LASCs that can be readily prepared from scandium chloride and sodium trisdodecylsulfate in water is scandium trisdodecylsulfate ([ScCDSIj]), shown in Figure... 

Kobayashi, S. and Wakabayashi, T., Scandium trisdodecylsulfate (STDS). A new type of Lewis acid that forms stable dispersion systems with organic substrates in water and accelerates aldol reactions much faster in water than in organic solvents, Tetrahedron Lett., 1998,39, 5389-5392. 

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