Recent Developments in Z‐Selective Olefin Metathesis Reactions by Molybdenum, Tungsten, Ruthenium, and Vanadium Catalysts

By focusing on recent developments on natural and non-natural azasugars (iminocyclitols), this review bolsters the case for the role of olefin metathesis reactions (RCM, CM) as key transformations in the multistep syntheses of pyrrolidine-, piperidine- and azepane-based iminocyclitols, as important therapeutic agents against a range of common diseases and as tools for studying metabolic disorders. Considerable improvements brought about by introduction of one or more metathesis steps are outlined, with emphasis on the exquisite steric control and atom-economical outcome of the overall process. The comparative performance of several established metathesis catalysts is also highlighted.

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Light guided chemoselective olefin metathesis reactions

Pure and Applied Chemistry ◽

10.1515/pac-2016-1221 ◽

2017 ◽

Vol 89 (6) ◽

pp. 829-840 ◽

Cited By ~ 7

Author(s):

Ofer Reany ◽

N. Gabriel Lemcoff

Keyword(s):

Chemical Reactions ◽

Olefin Metathesis ◽

Lessons Learned ◽

The Past ◽

Metathesis Reactions ◽

Catalytically Active ◽

Recent Developments ◽

Metathesis Catalysts ◽

External Stimuli ◽

Careful Design

AbstractAn appealing concept in synthetic chemistry is photo-induced catalysis; where dormant complexes become catalytically active upon activation with light. The ruthenium-based olefin metathesis complexes founded on the original Grubbs catalyst have probably been one of the most widely studied families of catalysts for the past 25 years. Greater stability and versatility of these olefin-metathesis catalysts has been achieved by careful design of the ligand sphere, including latent catalysts which are activated by external stimuli. This article describes our recent developments towards light-induced olefin metathesis reactions based on photoactive sulfur-chelated ruthenium benzylidene catalysts. Alternative chemical reactions, be it photo-induced olefin metathesis or other direct photochemical processes, by using light of different frequencies were studied in chemoselective chromatic orthogonal pathways. The lessons learned during the development of these reactions have given birth to selective photo-deprotection sequences and novel pathways for stereolithographic applications.

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Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

10.26434/chemrxiv.7130801.v1 ◽

2018 ◽

Author(s):

Haley Albright ◽

Paul S. Riehl ◽

Christopher C. McAtee ◽

Jolene P. Reid ◽

Jacob R. Ludwig ◽

...

Keyword(s):

Lewis Acid ◽

Olefin Metathesis ◽

Acid Activation ◽

Lewis Acid Catalysts ◽

Distinct Mode ◽

Aliphatic Ketones ◽

Carbon Carbon Bond ◽

Metathesis Reactions ◽

Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

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