Three-component synthesis of novel trifluoromethyl-containing tetrahydropyran derivatives

l-Proline-catalyzed reaction of ethyl 4,4,4-trifluoroacetoacetate, cinnamaldehyde and anilines provide a novel method for preparation of ethyl-6-(arylamino)-2-hydroxy-4-phenyl-2-(trifluoromethyl)tetrahydro-2H-pyran-3-carboxylate derivatives in good yields. The reaction was conducted by initial Michael addition, followed by intra-molecular cyclization under mild conditions. The structure of a typical ethyl-2-hydroxy-4-phenyl-6-(m-tolylamino)-2-(trifluoromethyl)tetrahydro-2H-pyran-3-carboxylate (4h) was confirmed by XRD analysis. A plausible mechanism is presented.