[EN] CATALYTIC ASYMMETRIC SYNTHESIS OF OPTICALLY ACTIVE alpha-HALO-CARBONYL COMPOUNDS [FR] SYNTHESE ASYMETRIQUE CATALYTIQUE DE COMPOSES DE DOLLAR G(A)-HALO-CARBONYLE OPTIQUEMENT ACTIFS
Enantioselective Protonation of Silyl Enol Ethers and Ketene Disilyl Acetals with Lewis Acid-Assisted Chiral Brønsted Acids: Reaction Scope and Mechanistic Insights
Enantioselectiveprotonation is a potent and efficient way to construct chiral carbons. Here we report details of the reaction usingLewisacid-assisted chiral Bronsted acids (chiral LBAs). The 1:1 coordinate complex of tin tetrachloride and optically active binaphthol ((R)- or (S)-BINOL) can directly protonate various silylenolethers and ketene disilyl acetals to give the corresponding α-aryl ketones
Design and Application of 2,2-Dibromodimedone as Organic Brominating Reagent for Asymmetric Bromination of 1,3-Dicarbonyl Compounds and Ketones Catalysed by Chiral Amino Acids
作者:Papori Goswami、Abhilasha Baruah、Babulal Das
DOI:10.1002/adsc.200900138
日期:2009.7
A green and ecofriendly enantioselective α‐bromination of carbonyl and 1,3‐dicarbonyl compounds is reported involving the synthesis of a novel organicbrominating source. The organicbrominatingreagent can be recovered after each cycle, rebrominated and reused. The reaction is catalysed by chiralaminoacids and completed within a short reaction time with good enantioselectivity and exclusive formation