Meerwin reaction

Arylation of activated double bonds with diazonium salts in the presence of copper catalysts is known as the Meerwin reaction. The reaction is postulated to either proceed through an organocopper intermediate or through a chlorine atom transfer from chiral CuCl complex to the a-acyl radical intermediate. Brunner and Doyle carried out the addition of mesityldiazonium tetrafluoroborate with methyl acrylate using catalytic amounts of a Cu(I)-bisoxazoline ligand complex and were able to obtain 19.5% ee for the product (data not shown) [79]. Since the mechanism of the Meerwin reaction is unclear, it is difficult to rationalize the low ee s obtained and to plan for further modifications. 

Apart from the Meerwin-Ponndorf-Verley (MPV) reaction,16 18catalytic asymmetric transfer hydrogenation has remained quite primitive,111,112 with successful examples of reduction of activated olefins, using alcohols or formic acid as hydrogen source, being reported only recently.113,114... 

The conversion of the product of Step 2 into 2-bromo-3-[4-methoxy-3-[N-(4-trifluoromethylbenzyl)]carbamoyl phenyl]amide is an example of the Meerwin-Schuster acylation reaction (1). 

Types of reactions such as Fridel-Crafts, Grignard, Meerwin-Ponndorf, Cannizzaro, Clemenson. Wolff-Kishner, Hofmann Degradation, Beckman Rearrangement, Simmons-Smith, Piels-Alder, Wurtz-Fitig, etc. may not be household names to everyone, but they are to many organic chemists. More importantly, literature sources can be searched for these classifications to give an overall perspective to a reaction under study. 

The aluminum-catalyzed hydride shift from the a-carbon of an alcohol component 2 to the carbonyl carbon of a second component 1 is named the Meerwin-Ponndorf-Verley reduction or Oppenauer oxidation depending on the isolated product. If aldehydes or ketones 4 are the desired products, the reaction is viewed as the Oppenauer oxidation. 3... 

His polymerization mechanism, therefore, is based on known reactions of metal alkoxides with carbonyl compounds. Side reactions, like a Meerwin-Ponndorf or a Tischenko, should be expected and were included into the reaction scheme ... 

Meerwin-Ponndorf-Verley reactions, using lanthanides... 

Early attempts to verify the stereochemical predictions of orbital symmetry control were hampered by carbocation rearrangement reactions/ such as Wagner-Meerwin shifts, although the very presence of these anomalous pathways is consistent with a cationic pathway. It is now well established that the Nazarov cyclization occurs via a pentadienyl cation 10,... 

Meerwin-Ponndorf-Verley (MPV) reduction of carbonyl compounds to alcohols is an important reaction in organic chemistry. Posner et al. (1977) carried out the efficient reduction of carbonyl compounds using isopropyl alcohol/diisopropyl carbinol and alumina under conventional heating, that has now been translated to a solvent less and expeditious reduction that uses aluminum alkoxides under micro-wave irradiation conditions and the reaction was completed in 2 min (Barbry and Torchy, 1997). 

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