| 摘要 |
32 A process for the synthesis of vinyl ethers of formula I wherein R1 and R2, each independently, represent hydrogen or a primary, secondary or tertiary alkyl group, R3 is hydrogen, a primary alkyl, phenyl, or substituted phenyl group, or R2 and R3, taken together, represent a polymethylene chain containing from 3 to 10 carbon atoms wherein one or more hydrogens can be replaced by methyl or ethyl groups, and R is a primary, secondary or tertiary alkyl group, which comprises reacting a suitably selected dioxolane derivative of formula II II wherein 33 R1, R2, and R3 are as defined above, and R4, R5, R6, and R7, each independently, represent hydrogen or an alkyl group, with a boric acid ester of formula III B (OR)3 III wherein R is as defined above, in the vapor phase, at a temperature comprised between 100 and 400 .degree.C, and in the presence of an acidic heterogeneous catalyst. |
