Question

Question 044 Which of the following sequences converts 2-methylpropene and sodium acetylide into 3-methylbutanal? 1) HBr; 2) NaCCH; 3) O3; 4) DMS 1) NaCCH; 2) H2/Ni2B; 3) O3; 4) DMS 1) HBr, ROOR; 2) NaCCH; 3) H2/Ni2B 4) O3; 5) DMS 1) HBr, ROOR; 2) NaCCH; 3) O3; 4) H2O 1) HBr; 2) NaCCH; 3) O3; 4) H2O

Answer 1

1) HBr; 2) NaCCH; 3) O3; 4) H2O

Step-by-step explanation:

The first step is formation of alkyl halide followed by reaction with sodium acetylide, to form 3-methylbutene, which is then followed by oxidation reaction with O3& H2O to 3-methylbutanal

Answer 2

The sequence of reagents' incorporation for the conversion of 2-methylpropene into 3-methylbutanal is option (C.):

1.
`HBr,ROOR` ; 2.
`NaCCH,H_(2)/Ni_(2)B` ; 3.
`O_(3), DMS`

Step-by-step explanation:

The summary of this reaction's mechanism is as follows:

• Radical hydro-halogenation of 2-methylpropene through a technique known as "peroxide effect" in which the HBr addition causes free radical formation of the alkene
• Nucleophilic SN2 substitution reaction (acetylide)
• Hydrogenation
• Ozonolysis of the alkene: after the addition reaction, the intermediate ozonide is converted to aldehyde using dimethyl sulfide (DMS)