enantioselectivities in methanol as the solvent. This may account for optimised steric and electroniceffects. However, by changing the solvent catalysts with other backbones can give rise to excellent results. This gives proof that simple correlations between steric and electronic properties and results in the enantioselective hydrogenation frequently claimed in literature are not general.
作者:R. Alan Aitken、Vidar Bjørnstad、Tracy Massil、Jan Skramstad
DOI:10.1080/10426509908546310
日期:1999.1.1
In an extension of our recent work on generating acetylenic amino acid derivatives by flashvacuumpyrolysis (FVP) of appropriate stabilised phosphorus ylides,1 we examined the ylides 1 with a free amino group. Rather than the expected acetylenic product these gave the novel cyclic ylides 2 with loss of ethanol. Preliminary attempts to bring about extrusion of Ph3PO from these gave rather confusing
Diphenylarsinoderivate des Maleins�ureanhydrids und verwandte Verbindungen. Kristall- und Molek�lstruktur des 2,3-Bis(diphenylstibino)maleins�ureanhydrids
作者:Dieter Fenske、Heinz Teichert、Heinz Prokscha、Werner Renz、Hermann J. Becher
DOI:10.1007/bf00938726
日期:——
Fleischhauer, Joerg; Asaad, Adel N.; Schleker, Wolfgang, Liebigs Annalen der Chemie, 1981, # 2, p. 306 - 311
In the present application protection is sought for compounds of the general formula (I) as ligands for reactions catalysed by transition metals. The preparation thereof and use thereof, in particular for the preparation of β-amino acids, is also discussed.