Correlation of gas phase proton affinities with SN2 nucleophilicities. A quantitative assessment of steric hindrance in SN2 reactions was written by McManus, Samuel P.. And the article was included in Journal of Organic Chemistry in 1981.Recommanded Product: 2-Isopropylpyridine This article mentions the following:
A method for quant. assessing steric hindrance originating primarily in a nucleophilic component is described. Good correlations (r > 0.985) are observed when nucleophilicities of 3- and 4-substituted pyridines reacting with either FSO3Me in Me2CHNO2 or EtI in PhNO2 are plotted against gas-phase proton affinities of the pyridine derivatives Observed nucleophilicities for 2-substituted pyridine derivatives fail to correlate with proton affinities because steric factors slow the rates of their SN2 reactions; hence, low nucleophilicity values are calculated Using the least-squares correlation line for 3- and 4-substituted pyridines, the proton affinities of 2-substituted pyridines may be used to predict steric-free nucleophilicities and, therefore, rates of reaction. These theor. values then give a quant. measure of steric retardation in SN2 reactions of 2-substituted pyridine derivatives A similar treatment was applied to alcs. reacting with Me tosylate and with pentamethyleneiodonium ion. There are moderate steric effects slowing the reactions of EtOH when the substrate is primary; bulkier alcs. show severe steric retardation in SN2 reactions. The present treatment is limited to nucleophiles with similar solvation and electrophilicity properties. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Recommanded Product: 2-Isopropylpyridine).
2-Isopropylpyridine (cas: 644-98-4) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Recommanded Product: 2-Isopropylpyridine