Question

Which of the following is/are nucleophiles?

• A. $\stackrel{\ominus }{OH}$
• B. $HS\stackrel{\ominus }{O_3}$
• C. $RCOCl$
• D. $R-\underset{..}{\stackrel{..}{O}}-R$

Answer 1

Answer: (A), (B), (D)

$R-\underset{..}{\stackrel{..}{O}}-R$

What are attacking Reagents?

Substrate Reagent Product Reagents are of two types: the one which attacks the positive site in the molecule is called the nucleophile or nucleophilic reagent and the one which attacks the negative site in the molecule is called the electrophile or electrophilic reagent.

Nucleophilic reagent or nucleophile: A negatively charged species or neutral molecule with lone pair of electrons, i. e., with electron-rich centre. They act as Lewis base, e. g

$\stackrel{\ominus }{O}H,\stackrel{\ominus }{O}R,\stackrel{\ominus }{C}N.\stackrel{\ominus }{N}{H}_2,\stackrel{\ominus }{H}\left(hydrideion\right),HS\stackrel{\ominus }{O_3},CO\stackrel{\ominus }{O},$

$R-C\equiv \stackrel{\ominus }{C},\stackrel{\ominus }{CH}(COOEt{)}_2,C{H}_3,\stackrel{\ominus }{COC{H}_2},H_2\stackrel{..}{O:},\underset{..}{\stackrel{..}{ROH}}$ $R-\underset{..}{\stackrel{..}{O}}R,R-\underset{..}{\stackrel{..}{S}}-H,R\underset{.}{-}\stackrel{..}{N{H}_2},\stackrel{..}{N{H}_3},$

$\stackrel{\ast }{R}MgX,\stackrel{\ast }{R}Li,LiAl\stackrel{\ast }{H_4}$

(Star indicates the atom that donates electron to the substrate.)

$Here,\stackrel{\ominus }{OH},HS{\stackrel{\ominus }{O}}_{3}andR-\underset{..}{\stackrel{..}{O}}-Rareelectron-rich.$