Method for synthesizing (E)-Anethol and Related Compounds By Cross Coupling Reaction of Potassium alllyltrifluroborate and 4-bromoanisole and aryl halides
申请人:AL-MASUM Mohammad
公开号:US20120010298A1
公开(公告)日:2012-01-12
Methods of producing substituted and non-substituted beta-methyl styrene by a cross-coupling reaction are provided. The disclosure also provides for methods of preparing (E)-Anethol and related compounds by a cross coupling reaction of potassium allyltrifluoroborate and 4-bromoanisole and aryl halides. Compounds, compositions, and methods of treating disorders utilizing beta-methyl styrene are also provided.
Remarkable regioselectivity in microwave-enhanced palladium-catalyzed allylation reaction involving allyltrifluoroborates and aryl halides
作者:Mohammad Al-Masum、Shahrina Alam
DOI:10.1016/j.tetlet.2009.06.134
日期:2009.9
An unprecedented cross-coupling reaction of potassium allyltrifluoroborates and arylhalides to the corresponding trans-β-methylstyrenes in the presence of PdCl2(dtbpf) catalyst under microwave heating was developed.
Cross-Coupling of Aromatic Bromides with Allylic Silanolate Salts
作者:Scott E. Denmark、Nathan S. Werner
DOI:10.1021/ja805951j
日期:2008.12.3
The sodium salts of allyldimethylsilanol and 2-butenyldimethylsilanol undergo palladium-catalyzed cross-coupling with a wide variety of aryl bromides to afford allylated and crotylated arenes. The coupling of both silanolates required extensive optimization to deliver the expected products in high yields. The reaction of the allyldimethylsilanolate takes place at 85 degrees C in 1,2-dimethoxyethane with allylpalladium chloride dimer (2.5 mol %) to afford 73-95% yields of the allylation products. Both electron-rich and sterically hindered bromides reacted smoothly, whereas electron-poor bromides cross-coupled in poor yield because of a secondary isomerization to the 1-propenyl isomer (and subsequent polymerization). The 2-butenyldimethylsilanolate (E/Z, 80:20) required additional optimization to maximize the formation of the branched (gamma-substitution) product. A remarkable influence of added alkenes (dibenzylideneacetone and norbornadiene) led to good selectivities for electron-rich and electron-poor bromides in 40-83% yields. However, bromides containing coordinating groups (particularly in the ortho position) gave lower, and in one case even reversed, selectivity. Configurationally homogeneous (E)-silanolates gave slightly higher gamma-selectivity than the pure (2)-silanolates. A unified mechanistic picture involving initial gamma-transmetalation followed by direct reductive elimination or sigma-pi isomerization can rationalize all of the observed trends.