Are carboxylic esters really refractory to DAST? On the fluorination of α-hydroxyesters with DAST
作者:Susan Lepri、Federica Buonerba、Paola Maccaroni、Laura Goracci、Renzo Ruzziconi
DOI:10.1016/j.jfluchem.2014.09.007
日期:2015.3
mixture of ethyl 2-(ethoxydifluoromethyl)-2-hydroxyalkanoates, 1,1-bis(ethoxydifluoromethyl)alkan-1-ols when administered at room temperature in dichloromethane. The reaction was exploited in the synthesis of nucleus- and side-chain polyfluorinated indoles. The fluorination of substituted diethyl 2-[(1-tert-butoxycarbonylindol-3-yl)methyl]-2-hydroxymalonates with DAST gave a mixture of ethyl 2-(ethoxy
2-烷基-2-羟基丙二酸二乙酯与DAST几乎完全在酯羰基处反应,在室温下施用时可得到2-(乙氧基二氟甲基)-2-羟基链烷酸乙酯,1,1-双(乙氧基二氟甲基)烷烃-1-醇的混合物在二氯甲烷中。该反应被用于合成核和侧链多氟吲哚。用DAST对取代的2-[((1-叔丁氧基羰基吲哚-3-基)甲基] -2-羟基丙二酸二乙酯进行氟化,得到乙基2-(乙氧基二氟甲基)-2-羟基-3-(1-叔丁氧基羰基吲哚的混合物-3-基)丙酸酯,非对映异构体1'-叔-丁氧基羰基-2'-羟基-2,2-二乙氧基羰基螺(环丙烷-1,3'-二氢吲哚)和仅痕量的1,1-双(乙氧基二氟甲基)-2- (1-叔-丁氧基羰基吲哚-3-基)乙醇。这些混合物的组成根据反应条件而变化。区域选择性取代的2-羟基-2-[((1-叔丁氧基羰基吲哚-3-基)甲基] -3,3,3-三氟丙酸乙酯与DAST在0°C的二氯甲烷中反应,得到令人满意的相应1-乙氧基-