Vanadium cyanates

Vacuum manifold system, 51,56 Vanadium oxyacetylacetonate, 50,56 N-Vinylpyrrolidone, cyanation,50,54... 

Avecia, a former part of the Zeneca Group, developed a range of cheap and highly active titanium- or vanadium-based salen catalysts called CACHy catalysts (Scheme 23). They are based on Jacobsen s salen technology, but they are much more reactive and can, for example, be used in concentrations as low as 0.1 mol% in the cyanation of aryl aldehydes. The catalysts show similar reactivity with alkyl aldehydes and ketones and are applicable to the synthesis of the commercially important mandelic acid derivatives. 

In 2004, Katsuki reported vanadium(v)-salen complex 10 catalysed Meerwein-Ponndorf-Verley (MPV) cyanation with excellent enantiocontrol (up to 98% enantiomeric excess) as shown in Scheme 9.4. In this system, the reaction was carried out with 2,4,6-collidine as a cocatalyst at 0 °C and produced adduct 12 with up to 90% enantiomeric excess however, this resulted in low conversion (25% for 24 h). When the reaction was carried out at... 

Scheme 9.4 Enantioselective vanadium salen 10 and salalen 11-catalysed Meerwein-Ponndorf-Verley (MPV) cyanation, reported by Katsuki. ...

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