The Baylis–Hillman chemistry in aqueous media: a convenient synthesis of 2-methylenealkanoates and alkanenitriles
摘要:
A convenient, general and efficient synthesis of 2-methylenealkanoates and alkanenitriles is accomplished via the regioselective nucleophilic (S(N)2') addition of hydride ion from NaBH4 to (2Z)-2-(bromomethyl)alk-2-enoates and 2-(bromomethyl)alk-2-enenitriles respectively in the presence of DABCO in environment friendly aqueous media. Synthesis of two hypoglycemic agents is also described. (C) 2001 Elsevier Science Ltd. All rights reserved.
Microwave-assisted synthesis of the (E)-α-methylalkenoate framework from multifunctionalized allylic phosphonium salts
作者:Lidiane Meier、Misael Ferreira、Marcus M. Sá
DOI:10.1002/hc.21001
日期:——
A convenient and general microwave-assisted method for the synthesis of stereochemicallydefined α-methylalkenoic acids and esters from allylic phosphonium salts in a basic aqueous medium is described. A selective preparation of acids or esters was dependent on the base (NaOH or NaHCO3) employed in the reaction and could be achieved with good to excellent yields under mild conditions in the absence
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
Pd-Catalyzed desulfitative arylation of olefins by <i>N</i>-methoxysulfonamide
作者:Subhadra Ojha、Niranjan Panda
DOI:10.1039/d1ob02360h
日期:——
A novel Pd-catalyzed protocol for the desulfitative Heck-type reaction of N-methoxy aryl sulfonamides with alkenes was reported. The cross-coupling reaction was performed successfully with a variety of olefins to obtain aryl alkenes. Different substituents on the aromatic ring of N-methoxysulfonamides were also found to be compatible with the reaction conditions. Expectedly, the reaction proceeds through
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.
The metal- and photocatalyst-free synthesis of substituted allylarenes has been carried out under visiblelightdriven conditions. The process was based on the photogeneration of aryl radicals from arylazosulfones and their ensuing reaction with allyl sulfones. The developed procedure was very efficient when using substrates bearing electron-withdrawing groups, and allowed for the preparation of α-benzyl