Specific Features of Reactions of Halomethyl Derivatives of 2-Isobutylfuran with Nucleophiles
作者:L. M. Pevzner
DOI:10.1007/s11176-005-0348-1
日期:2005.6
3,4- and 3,5-bis(chloromethyl)-2-isobutylfurans react with sodium diethyl phosphite by the Michaelis-Becker reaction scheme to form phosphonates whose yield significantly depends on the location of the halomethyl group in the furan ring. 3,4-Bis(chloromethyl)-2-isobutyl-5-methylfuran under analogous conditions gives a diphosphonate, while in 3,5-bis(chloromethyl)-2-isobutylfuran phosphorylation of the α-chloromethyl group competes with dehydrochlorination leading to a chloromethylated alkene, the second process being preferred. Further phosphorylation involves only one chloromethyl group of the alkene. Ethyl 5-(bromomethyl)-2-isobutylfuran-3-carboxylate reacts with sodium acetate to give a substitution product, while its isomer with the reverse location of the substituents eliminates hydrogen bromide exclusively. In the latter case, the acetate is formed only as a minor product.
3,4-和3,5-双(氯甲基)-2-异丁基呋喃与亚磷酸二乙酯钠通过Michaelis-Becker反应方案反应形成膦酸酯,其产率很大程度上取决于呋喃环中卤甲基的位置。 3,4-双(氯甲基)-2-异丁基-5-甲基呋喃在类似条件下产生二膦酸酯,而在3,5-双(氯甲基)-2-异丁基呋喃中,α-氯甲基的磷酸化与脱氯化氢竞争,导致氯甲基化烯烃,优选第二种方法。进一步的磷酸化仅涉及烯烃的一个氯甲基。 5-(溴甲基)-2-异丁基呋喃-3-甲酸乙酯与乙酸钠反应生成取代产物,而其取代基位置相反的异构体仅消除溴化氢。在后一种情况下,乙酸盐仅作为次要产物形成。