Yvo Crameri
Hoffmann-La Roche
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Publication
Featured researches published by Yvo Crameri.
Tetrahedron-asymmetry | 1991
Bernd Heiser; Emil Albin Broger; Yvo Crameri
Abstract A new synthetically useful method for the synthesis of the diphosphine ruthenium dicarboxylato complexes (PP)Ru(O2CR)2 (R = CF3 and CH3) is presented, which uses the easily accessible complex (COD)2Ru2(μ-O2CCF3)4 as starting material. This complex as well as (COD)Ru(η2-O2CCH3)2 and (COD)2Ru2Cl4(NCCH3) have been shown to be suitable precursor complexes for the in-situ preparation of ruthenium(II) dicarboxylato and dichloro complexes of atropisomeric diphosphines, respectively. The high efficacy of the preformed and in-situ generated ruthenium complexes as precatalysts is demonstrated in asymmetric hydrogenations of allylic alcohols, enamides, and a β-keto ester.
Tetrahedron-asymmetry | 1997
Yvo Crameri; Joseph Foricher; Michelangelo Scalone; Rudolf Schmid
Abstract A short, technically feasible route was developed for the synthesis of (S)2-(4-fluorophenyl)-3-methylbutanoic acid (S)- 2 with an overall yield of 80% starting from 4-fluorophenylacetic acid. Asymmetric hydrogenation of the easily accessible unsaturated acid 3 in the presence of ruthenium(II) carboxylato complexes containing chiral atropisomeric diphosphines afforded (S)- 2 in up to 94% ee. The ee of (S)- 2 was upgraded to 98% by crystallization of its sodium salt. The same protocol was also applied to the synthesis of (S)-2-(4-chlorophenyl)-3-methylbutanoic acid.
Pure and Applied Chemistry | 1996
Rudolf Schmid; Emil Albin Broger; Marco Cereghetti; Yvo Crameri; Joseph Foricher; Michel Lalonde; R. K. Müller; Michelangelo Scalone; G. Schoettel; Ulrich Zutter
Helvetica Chimica Acta | 1988
Hans Peter Märki; Yvo Crameri; Rainer Eigenmann; Anna Krasso; Henri Ramuz; Karl Bernauer; Murray Goodman; Kenneth L. Melmon
Archive | 1985
Emil Albin Broger; Yvo Crameri
Archive | 1979
Emil Albin Broger; Yvo Crameri; Hans Georg Wilhelm Leuenberger; Erich Widmer; Reinhard Zell
Archive | 1985
Emil Albin Broger; Yvo Crameri
Archive | 1983
Emil Albin Broger; Yvo Crameri
Archive | 1995
Emil Albin Broger; Yvo Crameri; Rudolf Schmid; Theodor Siegfried
Archive | 1988
Emil Albin Broger; Yvo Crameri; Bernd Heiser