Search results
Results from the WOW.Com Content Network
The Dowd-Beckwith ring expansion reaction is also capable of adding several carbons to a ring at a time, and is a useful tool for making large rings. [11] While it proceeds through an intermediate bicycle the final cyclization and ring opening take place within the same radical reaction . [ 12 ]
In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer (see figure). The reactive center can be radical, anionic or cationic. Ring-opening of cyclic monomers is often driven by the relief of bond-angle strain.
A ring forming reaction or ring-closing reaction in organic chemistry is an umbrella term for a variety of reactions that introduce one or more rings into a molecule. A heterocycle forming reaction is a reaction that introduces a new heterocycle. [1] [2] Important classes of ring forming reactions include annulations [3] and cycloadditions ...
Yields decrease as initial ring size increases, and the ideal use of TDR is for synthesis of five, six, and seven membered rings. A principal synthetic application of Tiffeneau–Demjanov ring expansion is to bicyclic or polycyclic systems. Several reviews on this reaction have been published. [1] [2] [3]
The mechanism of homogeneous ring-opening metathesis polymerization is well-studied. It is similar to any olefin metathesis reaction. Initiation occurs by forming an open coordination site on the catalyst. Propagation happens via a metallacycle intermediate formed after a 2+2 cycloaddition. When using a G3 catalyst, 2+2 cycloaddition is the ...
A pericyclic reaction is an organic reaction that proceeds via a single concerted and cyclic transition state, the geometry of which allows for the continuous overlap of a cycle of (π and/or σ) orbitals. The terms conrotatory and disrotatory describe the relative sense of bond rotation involved in electrocyclic ring-opening and -closing ...
Featuring Lisa Kudrow and Ray Romano, Netflix's new dark comedy "No Good Deed" is "about the highs and lows of searching for a safe, happy home."
The second step of the Buchner reaction involves a pericyclic concerted ring expansion. Based on Woodward–Hoffmann rules, the electrocyclic opening of norcaradiene derivatives is a 6-electron disrotatory (π 4 s + σ 2 s), thermally allowed process. ring opening. The norcaradiene-cycloheptatriene equilibrium has been studied extensively. [18]