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Medium Ring Ethers by Ring Expansion−Ring Contraction:  Synthesis of Lauthisan

Organic Letters, 2002
[reaction: see text] A new general method for the construction of medium ring ethers has been developed. This involves the ring expansion of halo-O,S-acetals followed by a Ramburg-Bäcklund ring contraction reaction with concomitant extrusion of the sulfur atom. This methodology has been utilized for the synthesis of cis- and trans-lauthisan.
Coster, M. J., De Voss, J. J.
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Ring Expansions of Nonpolar Polyphosphorus Rings

Chemistry – A European Journal, 2019
AbstractThe reaction of the phosphinidene complex [Cp*P{W(CO)5}2] (1 a) (Cp*=C5Me5) with the anionic cyclo‐Pn ligand complex [(η3‐P3)Nb(ODipp)3]− (2, Dipp=2,6‐diisopropylphenyl) resulted in the formation of [{W(CO)5}2{μ3,η3:1:1‐P4Cp*}Nb(ODipp)3]− (3), which represents an unprecedented example of a ring expansion of a polyphosphorus‐ligand complex ...
Martin Piesch, Michael Seidl, Markus Stubenhofer, Manfred Scheer   +3 more
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On Learning Ring-Sum-Expansions

SIAM Journal on Computing, 1990
Summary: Ring-sum-expansions (RSE) are representations of Boolean functions over the base \(\{\wedge,\oplus,1\}\), which reflect arithmetic operations in \(GF(2)\). \(k\)-RSE is the class of ring-sum-expansions containing only monomials of length at most \(k\). \(k\)-term-RSE is the class of ring-sum- expansions having at most \(k\) monomials.
Paul Fischer, Hans Ulrich Simon
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Visible‐Light Photocatalytic Intramolecular Cyclopropane Ring Expansion [PDF]

Angewandte Chemie - International Edition, 2017
Described herein is a new visible-light photocatalytic strategy for the synthesis of enantioenriched dihydrofurans and cyclopentenes by an intramolecular nitro cyclopropane ring expansion reaction.
Javier Luis-Barrera, VÍCTOR Laina-Martín, Thomas Rigotti   +2 more
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Ring expansion of isopropenyldihydrofuran derivatives

Journal of Heterocyclic Chemistry, 2006
Abstractmagnified imageLactonization of 2‐(hydroxymethyl)‐5‐isopropenyl‐4,5‐dihydrofuran‐3‐carboxylic acids 1a,b,c with dicyclohexylcarbodiimide gave the corresponding furano‐lactones, 5‐isopropenyl‐5,6‐dihydro‐1(3H)‐furo[3,4‐b]furanone 2a,b,c, which were readily converted to the corresponding oxepino‐lactones, 6‐methyl‐5,8‐dihydro‐1(3H)‐furo[3,4‐b ...
Seiji Yamaguchi, Nao Tsuchida, Kayoko Umeda, Hajime Yokoyama, Masahiro Miyazawa, Yoshiro Hirai   +5 more
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Ligand-modulated ring-expansion

Chemical Communications, 2019
An unstrained metal-containing macrocycle was ring-expanded by a ring-opening metathesis strategy, leading to the formation of a bimetallic dimeric macrocycle. The reaction is driven by coordination of a bulky ligand, 2,6-lutidine, on the fourth coordination site of the palladium center.
Veronica Carta, Miguel A. Soto, Mark J. MacLachlan   +2 more
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Ring expansion of cyclenones: an unusual regioselectivity

Journal of the Chemical Society, Chemical Communications, 1986
Various cyclenones have been homologated by a two-step sequence involving a reaction with α-selenoalkyl-lithium compounds and further reaction of the resulting β-hydroxyselenides with thallium(I) ethoxide in chloroform; an unusually high propensity of the alkyl groups to migrate in place of the vinyl moiety has been observed.
Krief, A., Laboureur, J.L.
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Ring Expansion and Ring Opening of Azetidines

ChemInform, 2007
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Couty, François, Evano, Gwilherm, Durrat, Francois   +2 more
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Hemiporphycene from the Expansion of a Corrole Ring

Angewandte Chemie International Edition, 2005
Formation of the vinylogous bridge between adjacent pyrrole rings (A and B) in the reaction of 5,10,15-triphenylcorrole with CI4 affords the corresponding hemiporphycene (see structure; N blue, I pink, C white, H green). This approach allows a facile preparation of functionalized hemiporphycenes.
PAOLESSE, ROBERTO, NARDIS, SARA, STEFANELLI, MANUELA, Fronczek F. R., Vicente M. G. H.   +4 more
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Ring expansion of nortricyclanone

Tetrahedron, 1965
Abstract Ring expansion of notricyclanone by the Tiffeneau—Demjanow procedure gave a mixture of two ketones in which tricyclo(2,2,2,0 2,6 )octan-8-one (1) largely predominated, the minor product being tricyclo(2,2,2,0 2,6 )octan-7-one (IV). A possible rationalization for the course of the ring expansion is discussed.
J.T. Lumb, G.H. Whitham
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