| 摘要 |
Preparing cyclic enol ethers of 2-methyl-2,3-dihydro-furan derivative (I) and/or 3,4-dihydro-2H-pyran derivative (II), comprises cyclization of a starting compound comprising pent-4-enal derivative (III), where the reaction is carried out as a reactive distillation in the presence of a Bronsted or Lewis acid, and the resulting cyclic enol ethers of the (I) and/or (II) are distillatively separated from the reaction mixture of the starting compound of (III). Preparing cyclic enol ethers of the 2-methyl-2,3-dihydro-furan derivative (I) and/or 3,4-dihydro-2H-pyran derivative (II), comprises cyclization of a starting compound comprising pent-4-enal derivative of formula (III), where the reaction is carried out as a reactive distillation in the presence of a Bronsted or Lewis acid, and the resulting cyclic enol ethers of the formulae (I) and/or (II) are distillatively separated from the reaction mixture of the starting compound (III). m : 0,1 or 2; either R 1>1-20C organic group; and R 2>H or 1-20C organic group; or R 1>+R 2>3-20C mono- or polycyclic ring system (optionally substituted and contains Si, N, P, O, and S); and R 3>, R 4>, R 5>H or 1-20C organic group. [Image]. |
