A facile two-step synthesis of methyl bis(2,2,2-trifluoroethyl)phosphonoacetate (Still–Gennari reagent) has been developed by exploiting Garegg–Samuelsson reaction conditions. Starting from trimethyl phosphonoacetate, Still–Gennari reagent was prepared in 94% yield via methyl 2-bis[(trimethylsilyl)oxy]phosphoryl}acetate intermediate. This synthetic procedure was also used to prepare some kinds of
Dealkylation Reaction of Acetals, Phosphonate, and Phosphate Esters with Chlorotrimethylsilane/Metal Halide Reagent in Acetonitrile, and Its Application to the Synthesis of Phosphonic Acids and Vinyl Phosphates
A mild and efficient method has been developed for carbon-oxygen bond cleavage using chlorotrimethylsilane/sodium iodide in acetonitrile. It was applied to synthetic transformation undernonaqueous and neutral conditions, such as acetal deprotection and the synthesis of phosphonic acids from the corresponding dialkyl phosphonates via methanolysis of their silyl esters. Effectiveness of various kinds
已经开发出一种在乙腈中使用三甲基氯硅烷/碘化钠进行碳氧键断裂的温和有效的方法。它被应用于非水和中性条件下的合成转化,如缩醛脱保护和从相应的膦酸二烷基酯通过其甲硅烷基酯的甲醇分解合成膦酸。通过 1 H NMR 在乙腈溶液中检测了各种金属碘化物或碘化铵对此类脱烷基作用的有效性。用碘化锂或碘化钾代替碘化钠也获得了令人满意的结果。然而,铜(I)或碘化季铵是无效的。乙腈中的氯三甲基硅烷/溴化锂对多功能膦酸酯或二烷基乙烯基磷酸酯的选择性脱烷基作用有效。
DEALKYLATION OF PHOSPHONATE ESTERS WITH CHLOROTRIMETHYLSILANE
作者:A. J. Gutierrez、E. J. Prisbe、J. C. Rohloff
DOI:10.1081/ncn-100002541
日期:2001.3.31
Chlorotrimethylsilane completely dealkylates phosphonateesters at elevated temperature in a sealed reaction vessel. These conditions are tolerated by a variety of functional groups and lead to high conversions of dimethyl, diethyl and diisopropyl phosphonates to their corresponding phosphonic acids.
Phosphonic acids having labile functional groups have been prepared quantitatively by the hydrolysis of bis(trimethylsilyl) phosphonates, were prepared by the reaction under mild conditions of the corresponding dialkyl phosphonates with bromotrimethylsilane.
Stereoselective Synthesis of the Benzodihydropentalene Core of the Fijiolides
作者:Timon Kurzawa、Klaus Harms、Ulrich Koert
DOI:10.1021/acs.orglett.8b00163
日期:2018.3.2
benzodihydropentalene core of fijiolides A and B has been achieved. The asymmetric conjugate addition of styrylboronic acid to an indenone produced the first stereocenter. Ring C was installed by ring-closing metathesis of a cis disubstituted indanone. Regioselective epoxide opening by NaSePh and subsequent oxidative elimination produced an allylic alcohol. The final introduction of the cyclopentadiene was possible