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A hydroxide ion acting as a nucleophile in an S N 2 reaction, converting a haloalkane into an alcohol. In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ...
the base is a poor nucleophile. Bases with steric bulk, (such as in potassium tert-butoxide), are often poor nucleophiles. For example, when a 3° haloalkane is reacts with an alkoxide, due to strong basic character of the alkoxide and unreactivity of 3° group towards S N 2, only alkene formation by E2 elimination is observed.
Work with the 2-adamantyl system (S N 2 not possible) by Schleyer and co-workers, [11] the use of azide (an excellent nucleophile but very poor leaving group) by Weiner and Sneen, [12] [13] the development of sulfonate leaving groups (non-nucleophilic good leaving groups), and the demonstration of significant experimental problems in the ...
The requirement for a good leaving group is still relaxed in the case of C=C bond formation via E1cB mechanisms, but because of the relative weakness of the C=C double bond, the reaction still exhibits some leaving group sensitivity. Notably, changing the leaving group's identity (and willingness to leave) can change the nature of the mechanism ...
The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of nucleophilic substitution is the hydrolysis of an alkyl bromide, R-Br under basic conditions, where the attacking nucleophile is hydroxyl (OH −) and the leaving group is bromide (Br −).
Alkoxides are strong bases [citation needed] and, when R is not bulky, good nucleophiles and good ligands. Alkoxides, although generally not stable in protic solvents such as water, occur widely as intermediates in various reactions, including the Williamson ether synthesis. [1] [2] Transition metal alkoxides are widely used for coatings and as ...
Carboxylate ions are good nucleophiles. They react with alkyl halides to form esters. The following reaction shows the reaction mechanism. [1]: 398–9 The S N 2 reaction between sodium acetate and bromoethane. The products are ethyl acetate and sodium bromide.
Others, however, insist that such a usage is an abuse of terminology, and limit the Michael addition to the formation of carbon–carbon bonds through the addition of carbon nucleophiles. The terms oxa-Michael reaction and aza-Michael reaction [2] have been used to refer to the 1,4-addition of oxygen and nitrogen nucleophiles, respectively. The ...