Preparation of a 3-thienylmalonic acid and the corresponding diesters
申请人:Oce-Andeno B.V.
公开号:US04262129A1
公开(公告)日:1981-04-14
Preparation of a 3-thienylmalonic acid or a diester thereof comprising reacting in a polar solvent in the presence of a copper (I) halide a thiophene compound of formula: ##STR1## wherein X=I or Br, R.sub.1 =H or a C.sub.1-4 alkyl group, R.sub.2 =H or a C.sub.1-2 alkyl group and R.sub.3 =H or a C.sub.1-2 alkyl group, with the proviso that R.sub.2 and R.sub.3 cannot be an alkyl group simultaneously, with a mono-deprotonated methylene compound of formula: ##STR2## wherein a cation is present and Z'=Z" is CN or COOR in which R is a C.sub.1-4 alkyl group, or Z'=CN and Z"=COOR' in which R' is a C.sub.1-2 alkyl group, followed by hydrolysis by methods known per se to get the corresponding free acid.
Palladium-Catalyzed Asymmetric Decarboxylative Lactamization of γ-Methylidene-δ-valerolactones with Isocyanates: Conversion of Racemic Lactones to Enantioenriched Lactams
A palladium-catalyzed asymmetric decarboxylative reaction of racemic gamma-methylidene-delta-valerolactones with aryl isocyanates has been developed to give enantioenriched 3,3-disubstituted 2-piperidones. High enantioselectivity has been achieved by tuning the ester group on substrate and the substituents of phosphoramidite ligand.