Steric effects

About: Steric effects is a research topic. Over the lifetime, 16112 publications have been published within this topic receiving 319615 citations. The topic is also known as: steric hindrance.

Conformational behavior of six-membered rings : analysis, dynamics, and stereoelectronic effects

Abstract: 100 years of conformational analysis stereodynamics of cyclohexane and substituted cyclohexanes, substitutent A-values ab initio studies of six-membered rings, present status and future developments molecular mechancis calculations of six-membered rings stereoelectronic effects in six-membered rings conformational analysis of six-membered sulfur-containing heterocycles steric and stereoelectronic effects in 1, 3, 2-dioxaphosphorinanes.

Amino Acid Binding by 2‐(Guanidiniocarbonyl)pyridines in Aqueous Solvents: A Comparative Binding Study Correlating Complex Stability with Stereoelectronic Factors

Abstract: A series of guanidiniocarbonylpyridine receptors has been synthesized, and these compounds bind amino acids (carboxylate forms) in aqueous DMSO with association constants ranging from K = 30 to 460 M−1 as determined by NMR titration experiments. The differences in the complex stabilities can be correlated with steric and electrostatic effects with the aid of calculated complex structures. For example, the electrostatic repulsion between the pyridine nitrogen lone pair and the bound carboxylate makes anion binding less efficient than with the analogous pyrrole receptors previously introduced by us for carboxylate binding in water. Furthermore, steric interactions between the receptor side chain as in 2 b and the bound substrate also disfavor complexation.

Understanding organic gas-phase anion molecule reactions.

Abstract: Although ionic reactions in the gas phase seem on the surface to be totally different from those in solution (e.g., they typically occur about 1012 times more rapidly than their solution analogues and go about as fast at 10 K as they do at room temperature), they can, in fact, exhibit subtle steric, electronic, and isotopic effects. In this Perspective, we show how these differences arise, explain why gas-phase ion reactions can be both fast and selective, and discuss when they can and cannot be classified as “hot” reactions. We also give examples of the use of these reactions to devise new synthetic pathways, investigate reaction mechanisms, and generate important thermochemical data such as bond dissociation energies.

Enhanced clickability of doubly sterically-hindered aryl azides

Abstract: Steric character is one of the most fundamental factors to determine the reactivity of the substrate in organic synthesis. In bimolecular reaction, the sterically-bulky group situated close to the reactive center generally prevents the approach of the reaction partner retarding the bond formation. This report describes, to the contrary, significantly enhanced reactivity of 2,6-disubstituted phenyl azides observed in catalyst-free 1,3-dipolar cycloaddition with alkynes, unexpectedly reacting faster than unsubstituted phenyl azide and even more faster than unhindered alkyl azide, despite the steric hindrance adjacent to the reactive azido group. Experimental and computational studies have indicated that the steric hindrance eliciting the inhibition of resonance between azido group and the aromatic ring is the primary cause of this apparently-paradoxical phenomenon. This is the first type of steric acceleration, indicating a possibility of designing a highly reactive functional group by strategically locating it in the sterically-congested environment.