N-Mesyloxylactams can undergo ring contraction either by C-3 (usually observed) or C-5 migration. C-5 migration can occur when the C-3 migration product possesses ring strain, but it does not usually compete with C-3 migration. The greater preference for C-3 migration is due to the carbonyl oxygen atom, which greatly stabilizes the intermediate.
When mixtures of carboxylic acids or their sodium salts and alcohols were treated with 2-chloro-1,3,5-trinitrobenzene in the presence of pyridine under mild conditions, the corresponding carboxylic esters were formed. The yields and the rates of the ester formation depended on the types of the acids and the alcohols used.
The present invention relates to the chemical synthesis of vittatalactone, the aggregation pheromone of the striped cucumber beetle,
Acalymma vittatum.
Aus Di- und Trimethyl-glutarsäuren, die z. T. nach verbesserten bekannten Methoden gewonnen wurden, hat man die entsprechenden Di- und Trimethyl-glutarsäure-anhydride und -imide hergestellt und letztere mittels LiAlH, in folgende Piperidin-methyl-Homologen uber- geführt : 3,5-Dimethyl-piperidin, 4,4-Dimethyl-piperidin, 3,S-Dimethyl-piperidin, 3,3,5-Trimethyl-piperidin und 3,4,4-Trimethyl-piperidin
Catalytic asymmetric desymmetrization of prochiral and meso compounds
申请人:——
公开号:US20040082809A1
公开(公告)日:2004-04-29
The present invention relates to methods for the synthesis of chiral non-racemic products, e.g., enantiomerically-enriched hemiesters, from prochiral and meso starting materials, e.g., prochiral and meso cyclic anhydrides. The present invention also relates to catalysts for the aforementioned methods, and methods for synthesizing these catalysts.