High-yielding sequential one-pot synthesis of chiral and achiral α-substituted acrylates via a metal-free reductive coupling reaction
作者:Dhevalapally B. Ramachary、Chintalapudi Venkaiah、Y. Vijayendar Reddy
DOI:10.1039/c4ob00667d
日期:——
A general process for the high-yielding synthesis of substituted chiral and achiral α-substituted acrylates was achieved through the sequentialone-pot combination of a metal-free reductive coupling reaction followed by an Eschenmoser methylenation. The proline catalyzed reaction of Meldrum's acid, aldehydes and Hantzsch ester followed by methylenation was successful with Eschenmoser's salt in the
cyclopentane/[PdCl(C3H5)]2 efficiently catalyses the Heck reaction of disubstituted alkenes such as methyl crotonate, ethyl cinnamate, methyl methacrylate or α-methylstyrene with a variety of aryl halides. In the presence of 1,2-disubstituted alkenes the stereoselectivities of the reactions strongly depend on the substituents of the alkenes. Selectivities up to 97% in favor of E-isomers can be obtained
顺式,顺式,顺式-1,2,3,4-四(二苯基膦甲基)环戊烷/ [PdCl(C 3 H 5)] 2有效催化巴豆酸甲酯,肉桂酸乙酯,甲基丙烯酸甲酯或α等二取代烯烃的Heck反应-甲基苯乙烯与各种芳基卤化物。在1,2-二取代的烯烃的存在下,反应的立体选择性强烈取决于烯烃的取代基。添加到巴豆酸甲酯中可以得到高达97%的选择性,有利于E-异构体。用1,1-二取代的烯烃获得甲基丙烯酸甲酯或α-甲基苯乙烯的产物混合物。
Pd-Catalyzed Threefold Arylation of Baylis-Hillman Bromides and Acetates with Triarylbismuth Reagents
作者:Maddali L. N. Rao、Somnath Giri
DOI:10.1002/ejoc.201200543
日期:2012.8
alkyl 2-benzylacrylates and 2-benzylacrylonitriles were synthesized by means of atom-economic cross-couplings of Baylis–Hillmanbromides or acetates with BiAr3 under palladium-catalyzed conditions. These reactions, involving threefold aryl couplings using BiAr3 reagents with bromides and acetates, are fast and are completed in 1–2 h with high product yields.
Process for preparing 2-(p-fluorophenyl)-2 methyl-propionic acid and
申请人:Hoechst Aktiengesellschaft
公开号:US05675034A1
公开(公告)日:1997-10-07
Process for preparing 3-(p-fluorophenyl)-2-methylpropionic acid and derivatives thereof of the formula (I), ##STR1## in which R is a hydroxy group, a linear or branched (C.sub.1 -C.sub.8)-alkoxy group, an aryloxygroup, an amino group or a (C.sub.1 -C.sub.8)-alkylamino group or a (C.sub.1 -C.sub.8)-dialkylamino group, by a) converting p-fluoroaniline into the p-fluorophenyldiazonium salt of the formula (II) ##STR2## in which X is the equivalent of an anion of an organic or inorganic acid having a pKa value of less than 7, b) reacting the diazonium salt of the formula (II) with a methacrylic acid derivative of the formula (III) ##STR3## in which R is as defined above in the presence of a palladium catalyst, if desired in the presence of a base and/or a solvent, to give the compounds of the formulae (IV) and (V) in which R is as defined above, ##STR4## and c) hydrogenating the resulting compounds of the formulae (IV) and (V) in the presence of a palladium catalyst with hydrogen.