Recent Developments of Arylboron Compounds as Lewis Acid Catalysts

Heteroatom-Substituted Delaminated Zeolites as Solid Lewis-Acid Catalysts

Carbocations as Lewis Acid Catalysts: Reactivity and Scope

One potential Lewis acid that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triaryl methylium ions as highly powerful Lewis acid catalysts for organic reactions. The Lewis acidity of the triaryl methylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is sho...

Ferrocenyl-derived electrophilic phosphonium cations (EPCs) as Lewis acid catalysts.

Oxidation of diphenylphosphinoferrocene and 1,1'-bis(diphenylphosphino)ferrocene with XeF2, resulted in the formation of CpFe(η(5)-C5H4PF2Ph2) 1 and Fe(η(5)-C5H4PF2Ph2)22 respectively. Subsequent reactions with [SiEt3][B(C6F5)4] yielded [CpFe(η(5)-C5H4PFPh2)][B(C6F5)4] 3 and [Fe(η(5)-C5H4PFPh2)2] [B(C6F5)4]24. PhP(η(5)-C5H4)2Fe 5 was prepared, converted to [PhMeP(η(5)-C5H4)2Fe][O3SCF3] 6 and th...

Bidentate Lewis acid catalysts in asymmetric synthesis*

The chemistry of bidentate Lewis acids belongs to an unexplored field of science, and so far has been only poorly studied. This paper illustrates the design of several bidentate Al and Ti Lewis acids, and their successful application to selective organic synthesis, particularly to asymmetric synthesis. For example, a new, chiral bidentate Ti(IV) complex is successfully designed by adding commer...

Microbial conversion of steroid compounds: recent developments

Steroid compounds can be ranked among the most widely marketed products from the pharmaceutical industry. Highly specific reactions are required to produce functionalized compounds with therapeutic use and commercial value. The complexity of steroid molecules renders the use of biocatalysts particularly interesting, due to the high regioand stereo-selectivity of the reactions to be performed. T...