- Synthesis of β-monosubstituted α,β-unsaturated amides with z-selectivity using diphenylphosphonoacetamides
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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.
- Kojima, Satoshi,Hidaka, Tsugihiko,Ohba, Yuko
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p. 515 - 523
(2007/10/03)
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