|
In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of reactions in which an electron nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom or a group of atoms to replace a so-called leaving group; the positive or partially positive atom is referred to as an electrophile. The whole molecular entity of which the electrophile and the leaving group are part is usually called the substrate.〔J. March, ''Advanced Organic Chemistry'', 4th ed., Wiley, New York, 1992.〕〔R. A. Rossi, R. H. de Rossi, ''Aromatic Substitution by the SRN1 Mechanism, ACS Monograph Series No. 178, American Chemical Society, 1983. (0-8412-0648-1 ).〕 The most general form for the reaction may be given as the following: :Nuc: + R-LG → R-Nuc + LG: The electron pair (:) from the nucleophile(Nuc) attacks the substrate (R-LG) forming a new bond, while the leaving group (LG) departs with an electron pair. The principal product in this case is R-Nuc. 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 the OH− and the leaving group is Br−. :R-Br + OH− → R-OH + Br− Nucleophilic substitution reactions are commonplace in organic chemistry, and they can be broadly categorised as taking place at a saturated aliphatic carbon or at (less often) an aromatic or other unsaturated carbon centre.〔L. G. Wade, ''Organic Chemistry'', 5th ed., Prentice Hall, Upper Saddle RIver, New Jersey, 2003.〕 == Saturated carbon centres == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nucleophilic substitution」の詳細全文を読む スポンサード リンク
|