Highly Enantioselective Synthesis of 3-Hydroxy-2-methylpropanoic Acid Esters through Ruthenium-SYNPHOS®-Catalyzed Hydrogenation: Useful Building Blocks for the Synthetic Community
Both enantiomers of 3-hydroxy-2-methylpropanoic acid tert-butyl ester were prepared with high enantioselectivity (up to 94 %) through a ruthenium-SYNPHOS®-promoted asymmetrichydrogenation reaction using an atom-economic transformation from simple and inexpensive precursors.
Asymmetric synthesis of chiral Roche ester and its derivatives via Rh-catalyzed enantioselective hydrogenation with chiral phosphine-phosphoramidite ligands
, known as the Roche ester, was prepared with high enantioselectivity (up to 96.7% ee) via the Rh-catalyzedasymmetrichydrogenation of methyl 2-hydroxymethylacrylate with a chiral 1,2,3,4-tetrahydro-1-naphthylamine-derived phosphine-phosphoramidite ligand (THNAPhos 5a) even at a low catalyst loading (0.1 mol %). An investigation on the substrate scope revealed that the ester group present in the substrate
Convenient General Asymmetric Synthesis of Roche Ester Derivatives through Catalytic Asymmetric Hydrogenation: Steric and Electronic Effects of Ligands
and concise asymmetrichydrogenation of acrylate esters promoted by the cationic ruthenium monohydride complex [Ru(H)(η6-cot)SYNPHOS]+BF4− is reported. A full investigation of the effects of catalyst precursors, solvents, temperature, hydrogen pressure, substrates as well as steric and electronic properties of ligands was carried out. The corresponding valuable Rocheesterderivatives were obtained
The present invention relates to the chemical synthesis of vittatalactone, the aggregation pheromone of the striped cucumber beetle,
Acalymma vittatum.
Biology-Oriented Synthesis of Stereochemically Diverse Natural-Product-Derived Compound Collections by Iterative Allylations on a Solid Support
作者:Jayant D. Umarye、Torben Leßmann、Ana B. García、Victor Mamane、Stefan Sommer、Herbert Waldmann
DOI:10.1002/chem.200601698
日期:2007.4.16
A strategy aiming at the introduction of stereocenters into polymer-bound natural-product-derived and -inspired compoundcollections is presented. Treatment of immobilized aldehydes with Brown's pinene-derived allylboranes results in the stereoselective formation of homoallylic alcohols with up to 89 % ee (ee=enantiomeric excess). Subsequent iterative ozonolysis-allylation sequences with up to three