Cross-coupling catalyst-controlled

The control of reactivity to achieve specific syntheses is one of the overarching goals of organic chemistry. In the decade since the publication of the third edition, major advances have been made in the development of efficient new methods, particularly catalytic processes, and in means for control of reaction stereochemistry. For example, the scope and efficiency of palladium- catalyzed cross coupling have been greatly improved by optimization of catalysts by ligand modification. Among the developments in stereocontrol are catalysts for enantioselective reduction of ketones, improved methods for control of the... 

The first total synthesis of quadrigemine C, a higher-order member of the polypyrrolidinoindoline alkaloid family was published by L. Overman et a. Key steps included a double Stille cross coupling and catalyst-controlled double... 

Commercially, pyridine is prepared by the gas phase, high-temperature reaction of crotonaldehyde, formaldehyde, steam, air, and ammonia over a silica-alumina catalyst in 60-70% yield. However, in the laboratory, the challenge is in the preparation of substituted pyridine derivatives in a process that allows one to control regioselectivity and chemoselectivity in the most efficient manner. In this regard the utility of palladium-catalyzed cross-coupling reactions has enabled synthetic chemists by providing the ability to construct highly diversified pyridine derivatives in an efficient fashion [2]. 

The Hayashi methodology is particularly interesting as the original pre-catalyst Fe(acac)3 had already been reported as the best candidate for the coupling between aryl and vinyl halides in THF. This means that improved control over the selectivity of this cross-coupling is achieved just by changing the nature of the solvent. 

Catalyst-Controlled Directing Groups in Cross-Dehydrogenative Coupling 181... 

Manabe K, Yamaguchi M (2014) Catalyst-controlled site-selectivity switching in Pd-catalyzed cross-coupling of dihaloarenes. Catalysts 4 307-320... 

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