485809-17-4Relevant academic research and scientific papers
Synthesis of β-monosubstituted α,β-unsaturated amides with z-selectivity using diphenylphosphonoacetamides
Kojima, Satoshi,Hidaka, Tsugihiko,Ohba, Yuko
, p. 515 - 523 (2007/10/03)
The utility of diphenylphosphonoacetamides [(PhO)2P(O)CH 2CONRR′] as Horner-Wadsworth-Emmons reagents was examined with five different patterns of substitution upon the amide nitrogen atom (2a: R, R′ = CH2Ph; 2b: R = CH2Ph, R′ = H; 2c: R = Me, R′ = OMe; 2d: R, R′ = Ph; 2e: R, R′ = (CH2) 4). The reaction of 2a was found to be Z-selective for aromatic aldehydes with selectivities up to 95:5. Reagent 2b led to reasonable selectivity for both benzaldehyde (85:15) and 3-phenylpropionaldehyde (87:13), while 2c was somewhat effective for only the latter alkyl aldehyde (83:17). Compounds 2d and 2e exhibited slightly lower selectivities compared with 2a.
Catalytic asymmetric epoxidation of α,β-unsaturated amides: Efficient synthesis of β-aryl α-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation - Pd-catalyzed epoxide opening process
Nemoto, Tetsuhiro,Kakei, Hiroyuki,Gnanadesikan, Vijay,Tosaki, Shin-Ya,Ohshima, Takashi,Shibasaki, Masakatsu
, p. 14544 - 14545 (2007/10/03)
The catalytic asymmetric epoxidation of α,β-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 α,β-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 β-aryl α-hydroxy amides, including β-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. Copyright
