cycloaddition

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cycloaddition

[¦sī·klō·ə′dish·ən]
(organic chemistry)
A reaction in which unsaturated molecules combine to form a cyclic compound.
References in periodicals archive ?
Relying on their high strain energy cyclopropanes, as carriers of the most fundamental ring geometry, offer a unique reactivity which allows for a multitude of transformations being grouped in ring-opening reactions, cycloadditions and rearrangements.
Included are stereoselective oxidation and reduction methods; stereoselective additions; cyclizations; metatheses and different types of rearrangements; asymmetric transition-metal-catalyzed, organocatalyzed, and biocatalytic reactions; methods for the formation of carbon-heteroatom and heteroatom-heteroatom bonds like asymmetric hydroamination and reduction amination, carboamination and alkylative cyclization, cycloadditions with carbon-heteroatom bond formation, and stereoselective halogenations; and methods for the formation of carbon-sulfur and carbon-phosphorus bonds and asymmetric sulfoxidation.
The contributions describe approaches for conjugating proteins and peptides to polymers, generating complex macromolecular architectures via orthogonal and selective cycloadditions, fabricating alkyne and azide functionalized surfaces, and designing multifunctional network polymers.
IMPROVED REGIOSELECTIVITY FOR [3+2] CYCLOADDITIONS AT ROOM TEMPERATURE, Jeanne L.
Functionalization of carbon nanotubes via 1,3-dipolar cycloadditions.
On the trans-cis controversy in Ti-TADDOLate-catalysed cycloadditions.
The development of reliable force-field models along with experimental studies to test predictions made are being carried out to define the important factors affecting stereoselectivities in synthetically significant reactions such as hydrosilylations and some cycloadditions.
Thus, there are four chapters on carbon-carbon bond forming reactions (enolate alkylations, organometal additions to carbonyls, aldol and Michael reactions, and cycloadditions and rearrangements), one chapter on reductions and hydroborations (carbon-hydrogen bond forming reactions), and one on oxidations (carbon-oxygen and carbon-nitrogen bond forming reactions).
Also discussed are the reactions of cascade cyclizations, heterocyclization involving enyne-carbodiimides, and new achievements in some classical cycloaddition reactions, such as the Diels-Alder condensation with acetylenic dienophiles, [2+2] cycloadditions with an acetylene component leading to the creation of a cyclobutene ring, and new results in cyclobutene syntheses by [2+2] acyclization of phosphorus containing 1,3-butadiene derivatives synthesized starting with propargyl-type alcohols.
The chapters in the second volume discuss the roles of microwaves in cycloadditions, organic synthesis catalysis, polymer chemistry, transition metal-catalyzed coupling reactions, combinatorial and high-throughput synthesis multicomponent reactions, radiochemistry, photochemistry, solid-phase peptide synthesis, fullerene and carbon nanotube chemistry, and extraction of essential oils.
In the process of investigating the use of vinylboronic esters in nitrile oxide cycloadditions, we became interested in how various dipolarophiles compare in reactivity with nitrile oxides generated under Mukiyama conditions.
Ghosez employed keteneiminium and nitrosocarbamyl reagents prepared from chiral amides to effect 2 + 2 and 2 + 4 cycloadditions with high enantioselectivity.