Lanthanum-catalysed reactions

Binary caesium-lanthanum oxides supported on the mesoporous molecular sieve MCM-41 have potential catalytic applications for base-catalysed reactions. A Cs MAS NMR study of this system revealed shorter Cs-0 bond lengths in the... 

Inspection of the data reveals a clear inverse correlation (with the exception of a few scattered data points) between the ionic radii of the various tripositive lanthanide ions and the extent of nitration whereby the the heavier congeners are the most effective. Thus lanthanum(IH) (Z = 57) triflate gave a 64% conversion of naphthalene to mononitronaphthalenes over lh, whereas the ytterbium(HI) (Z =70) triflate catalysed reaction gave a >95% conversion over the same time period. 

Reports which have clear applications in DNA hydrolysis include one of a dinuclear lanthanum(III) complex that catalyses phosphate diester hydrolysis to give unprecidented rates of reaction and one describing the preparation of two new dinuclear bisimidazolyl-Cu(II) calixarenes and an investigation of these complexes as metalloenzyme models for phosphate diester cleavage. The importance of tuning microenvironments when designing synthetic nucleases is illustrated by a report that intramolecular trans-esterification of 2-hydroxy-propyl-4-nitrophenyl phosphate (84) is up to 5000 times faster in organic solvents than in water/ ... 

The reaction of furfural with anilines has been known since 1850 a controlled process is now available for its reaction with amines, catalysed by lanthanum or scandium triflate, forming trans-4,5-diamino-2-pentenones. ... 

Recently, the You group reported the ehiral NHC/Lewis acid catalysed [4 + 2] annulation of 2-bromoenals bearing a y-hydrogen with isatin derivatives. In the presence of lanthanum triflate, the reaction went smoothly (Scheme 20.52). 

Lanthanum alkoxides have been used in the catalysed transhydrocyanation from acetone cyanohydrin to other aldehydes or ketones and also in the reactions of silyl... 

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