Asymmetric α-Benzoyloxylation of β-Ketocarbonyls by a Chiral Primary Amine Catalyst

Abstract

The direct asymmetric α-benzoyloxylation of β-ketocarbonyls catalyzed by a chiral primary amine is described herein. This protocol demonstrates excellent enantioselectivity for a broad range of substrates, which allows convenient access to highly enantioenriched α-hydroxy-β-ketocarbonyls.

Chiral Primary Amine/Palladium Dual Catalysis for Asymmetric Allylic Alkylation of β‐Ketocarbonyl Compounds with Allylic Alcohols

“…On the basis of a previous report,8d the absolute configuration of the newly formed quaternary stereocenter was assigned to be S 10. 13 Accordingly, Si ‐facial attack of the π‐allylpalladium complex on the enamine intermediate can be proposed to account for the observed stereoinduction (Figure 1). In this mode, steric effects play a key role in channeling the attack of the π‐allylpalladium species, for which a notable H‐bonding site is lacking.…”

Chiral Primary Amine/Palladium Dual Catalysis for Asymmetric Allylic Alkylation of β‐Ketocarbonyl Compounds with Allylic Alcohols

“…On the basis of ap revious report, [8d] the absolute configuration of the newly formed quaternary stereocenter was assigned to be S. [10,13] Accordingly, Si-facial attack of the p-allylpalladium complex on the enamine intermediate can be proposed to account for the observed stereoinduction ( Figure 1). In this mode,s teric effects play ak ey role in channeling the attack of the p-allylpalladium species,f or which anotable H-bonding site is lacking.The observed effect of bulky substituents on the tertiary amino moiety is clearly in support of this steric model (Table 1).…”

Cover Picture: (Prop., Explos., Pyrotech. 6/2013)

“…Then with the help of P 2 O 5 , a tricyclic molecular skeleton 6 was formed, with the yield of 65% 12. Moreover, the hydroxy group could easily react with phenylacetyl chloride, affording 7 with 99% yield and 99% ee (Scheme ) 13…”