How To Treat A Grignard Reagent As An Alkyl

 Comment: Treat a Grignard reagent as an alkyl nucleophile i.e. CH3MgBr is equivalent to CH3- nucleophile.

The Grignard reagent can also react with RX to form a longer chain alkane.
Example: CH3CH2MgBr + CH3CH2Br  CH3CH2CH2CH3 + MgBr2

In general, basicity parallels nucleophilic strength since both of them depend on the availability of the lone pair of electrons. The Grignard reagent is not only able to function as a nucleophile; it can operate as a base too by reacting with water to form an alkane.
Example: CH3CH2MgBr + H2O  CH3CH3 + Mg(OH)Br

Based on the diagonal relationship in the Periodic Table, lithium can be used as a substitute for magnesium. This class of organometallic compounds are called Gilman reagents.
For
It is first oxidised to a methyl ketone before it gets further oxidised to a carboxylate salt.
Stage 1: Oxidation to methyl ketone

oxidation half-equation:
RCH(OH)CH3  RCOCH3 [O already balanced]
RCH(OH)CH3  RCOCH3 + 2H+ [balance H atoms]

RCH(OH)CH3 + 2OH-  RCOCH3 + 2H+ + 2OH- [add OH- to remove H+]

RCH(OH)CH3 + 2OH-  RCOCH3 + 2H2O + 2e ----- (1) [balance the charge]

reduction half-equation:
I2 + 2e  2I- ----- (2)

Combine equations 1 and 2:
RCH(OH)CH3 + 2OH- + I2  RCOCH3 + 2H2O + 2I- [equation for Stage 1]

Stage 2: Oxidation to carboxylate salt [mechanism will be discussed in Section 3.7: Carbonyl Compounds] RCOCH3  RCOO-
RCOCH3  RCOO- + CHI3 [balance C by adding CHI3]
RCOCH3 + 3I2  RCOO- + CHI3 + 3I- [balance I by adding I2 and I-]
RCOCH3 + H2O + 3I2  RCOO- + CHI3 + 3I- [balance O atoms]
RCOCH3 + H2O + 3I2  RCOO- + CHI3 + 3I- + 4H+ [balance H atoms]
RCOCH3 + H2O + 3I2 +4OH-  RCOO- + CHI3 + 3I- + 4H+ +4OH- [add OH- to remove H+]

RCOCH3 + 3I2 + 4OH-  RCOO- + CHI3 + 3I- + 3H2O [equation for Stage 2]

Combining equations for stage 1 and 2:
RCOCH3 + 4I2 + 6OH-  RCOO- + CHI3 + 5I- +