Catalytic asymmetric epoxidation of alpha,beta-unsaturated amides: efficient synthesis of beta-aryl alpha-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process.
The catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process, was developed. This method was successfully utilized for the efficient synthesis of beta-aryl alpha-hydroxy amides, including beta-aryllactyl-leucine methyl esters. Interestingly, it was found that beneficial modifications on the Pd catalyst were achieved by the constituents of the first epoxidation, producing a more suitable catalyst for the Pd-catalyzed epoxide opening reaction in terms of chemoselectivity.
Nemoto
Tetsuhiro
T
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
Kakei
Hiroyuki
H
Gnanadesikan
Vijay
V
Tosaki
Shin-Ya
SY
Ohshima
Takashi
T
Shibasaki
Masakatsu
M
D000438:Alcohols / Q000138:chemical synthesis*; D000475:Alkenes / Q000737:chemistry*; D000577:Amides / Q000138:chemical synthesis*; D002384:Catalysis; D004852:Epoxy Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry; D013237:Stereoisomerism
D000438:Alcohols; D000475:Alkenes; D000577:Amides; D004852:Epoxy Compounds; D010165:Palladium