Cyclic enediol phosphoranes obtained from the reaction of trimethyl phosphite with biacetyl and hexafluorobiacetyl give strikingly different acylation products
作者:Fausto Ramirez、James F. Marecek
DOI:10.1016/s0040-4020(01)91291-8
日期:1984.1
exclusively the product of endocyclic O-acylation, dimethyl(2-acetoxy-cis-1,2, -bistrifluoromethylvinyl) phosphate. Acylation of the biacetyl-TMP phosphorane gives mixtures of the product of exocyclic O-acylation (a cyclic enediol phosphate) and the product of C-acylation (an α-hydroxy-β-diketone phosphate), the proportions depending on the structure of the acyl halide and the solvent. The parent 1,3,2-dioxaphospholene
由α-二酮,RCOCOR和亚磷酸三甲酯(TMP)制备的环状烯二醇膦(2,2,2-三甲氧基-2,2-二氢-1,3,2-二氧杂磷杂环戊烯)可提供截然不同的酰化产物,具体取决于在二氧杂磷环中具有五价磷的基团R的4,5-位的电子性质。乙酰氯或溴化物与六氟联乙酰-TMP膦烷反应仅得到内环O-酰化的产物二甲基(2-乙酰氧基-顺-1,2,-双三氟甲基乙烯基)磷酸酯。联乙酰基-TMP膦的酰化作用是环外O-酰化产物(环状烯二醇磷酸酯)和C-酰化产物(α-羟基-β-二酮磷酸酯)的混合物,其比例取决于其结构。酰卤和溶剂。母体1,3,2-二氧杂磷烯,即