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15 Μαρ 2018 · Employing CN − as a nucleophile and Cl − as a leaving group, they investigated substitution patterns on the alkyl halide, including α- and β-methylation, adjacent unsaturated functional groups (allyl, benzyl, propargyl, α to carbonyl), ring size, and α-halogenation and cyanation.
12 Απρ 2011 · Good Leaving Groups Are Weak Bases. A leaving group(a.k.a. “nucleofuge”) is the new Lewis base that is generated in various substitution and elimination reactions when a new bond is formed to carbon.
The leaving group is usually displaced with a negative charge The best leaving groups are those with atoms or groups that can best stabilize a negative charge.
1 Σεπ 2022 · Apart from sulphates and sulfonates, other esters of inorganic acids have been used as leaving groups in glycosylation reactions. As already stated in the introduction, phosphite and phosphate esters are well-established leaving groups, while few examples are described for anomeric nitrates.
26 Ιαν 2024 · Leaving propensity follows the opposite trend i.e., \(\ce{-I}\) is the best-leaving group, while \(\ce{-F}\) is the worst leaving group. \(\ce{-F}\) does not act as a leaving group. Basicity decreases from right to left in a row of the periodic table.
At the CCSD(T)/TZ2Pf+diff level it was shown that only Cl and SH are better leaving groups than F and lead to exothermic reactions. For the other leaving groups, the reactions are mildly (LG=CN) to substantially endothermic (LG=PH 2, OH, NH 2).
6 Αυγ 2007 · Overall: A good substrate for bimolecular nucleophilic substitution should have: 1. Weak C-L bond 2. Polarizable C-L bond (ease with which the electron distribution in the bond is distorted) 3. Leaving group that can accommodate a pair of electrons
