Complicated goings-on in the metal-manipulated ring-opening of cyclobutene.

On the ring-opening of substituted cyclobutene to benzocyclobutene: analysis of pi delocalization, hyperconjugation, and ring strain

On the ring-opening of substituted cyclobutene to benzocyclobutene: analysis of π delocalization, hyperconjugation, and ring strain.

The influence of several substituents on the ring-opening elementary step of cyclobutene-like systems is analyzed computationally in detail. We focus on trans-1,2-disiloxycyclobutene-like molecules. Electronic effects (hyperconjugation and π delocalization) and geometrical constraints are decoupled and allow for an instructive analysis. It is found that the energy difference between closed and ...

Substituent effect of group 14 elements on the ring-opening reaction of cyclobutene.

A series of cyclobutenes bearing group 14 elements at the 3-position were synthesized, and their thermal ring-opening reactions were studied. Carbon-substituted cyclobutene underwent the ring-opening reaction through an outward pathway to afford the E-diene exclusively. On the other hand, the ring-opening reaction of the silyl, germyl, and stannyl substituted cyclobutenes occurred in both outwa...

Precision Synthesis of Alternating Copolymers via Ring-Opening Polymerization of 1-Substituted Cyclobutenes.

Investigation of complex molecular systems depends on our ability to correlate physical measurements with molecular structure. Interpretation of studies that rely on synthetic polymers is generally limited by their heterogeneity; i.e., there is variation in the number and arrangement of the monomeric building blocks that have been incorporated. Superior physics and biology can be performed with...

Reaction pathways by quantum Monte Carlo: insight on the torsion barrier of 1,3-butadiene, and the conrotatory ring opening of cyclobutene.

Quantum Monte Carlo (QMC) methods are used to investigate the intramolecular reaction pathways of 1,3-butadiene. The ground state geometries of the three conformers s-trans, s-cis, and gauche, as well as the cyclobutene structure are fully optimised at the variational Monte Carlo (VMC) level, obtaining an excellent agreement with the experimental results and other quantum chemistry high level c...