| Abstract
| - A series of chiral vanadyl(V) methoxides bearing 3-t-butyl-5-substituted N-salicylene-l-valinate and l-t-leucinate as chiral auxiliaries has been prepared. In all cases except the 3,5-di-t-butyl analogue, theyexist as monomers both in solution and in the single crystal state. In the case of the 3,5-di-t-butyl analogue,the architectural nature of the vanadyl(V) complex highly depends on the base used during the complexformation event. A pentanuclear C4-symmetric complex was formed when potassium salts were employedinstead of the corresponding sodium salts. A central vanadate(V) unit serves to grip four identical chiralmonomeric vanadyl(V) units together, by which a potassium ion sits on top of the four flanking unitsthrough carbonyl coordinations and serves to hold the whole cluster by cooperation with the centralvanadate(V) unit. In comparison with the corresponding monomeric vanadyl(V) methoxide complex, thecluster complex was utilized to facilitate the asymmetric aerobic oxidations of various racemicα-hydroxyesters, -amides, and -thioesters with excellent selectivity factors (krel 40 to >500).
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