Choose the correct set of reagents for the following conversion trans Ph - CH = CH - CH 3 → &#160…

Choose the correct set of reagents for the following conversion
transPh-CH=CH-CH3→ cis Ph-CH=CH-CH3
  1. Br2, alc KOH,NaNH2,NaLiqNH3

  2. Br2, alc KOH,NaNH2,H2

    Lindlar Catalyst

  3. Br2,aqKOH,NaNH2,H2 Lindlar Catalyst
  4. Br2, aq KOH,NaNH2,NaLiqNH3

Solution

A trans alkene can be converted to a vicinal dihalide through a halogenation reaction. The vicinal dihalide can undergo double elimination to afford an alkyne. The alkyne can undergo partial reduction to give a cis alkene.

The reagents needed to convert trans(Ph - CH = CH - CH3) to cis-(Ph - CH = CH - CH3) are shown in the reaction scheme below.

 

 

Asked in: JEE Main 2023 (31 Jan Shift 1)

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