2-Methyl-2-butene can be synthesized using Wittig reaction in following steps;
1) First of all react Bromoethane with Triphenylphosphine which will undergo SN² reaction to produce Phosphonium salt. Phoshonium salt on treatment with base gives Phosphorous Ylide.
2) The ylide formed when treated with acetone forms a four membered ring intermediate, which readily rearranges to produce 2-methyl-2-butene and triphenylphosphine oxide.
Result:
Starting materials are...
1) Bromoethane
2) Acetone
3) Triphenyl phosphene
