Question

Complete the curved arrow mechanism of the following double elimination reaction when 1,2-dibromopropane is treated with two equivalents of sodium amide and heated in mineral oil. a) Use three curved arrows to show the elimination of the first hydrogen bromide. b) Use three curved arrows to show the elimination of the second hydrogen bromide. ENHE •NH HC Hac Bra , -NH3, Br c) Complete the structure of the organic product formed from the double elimination. N-H H3C- C-

Answer 1

TAnwer Hno a B7 U HC- & -c-4_nih zc- -I Br H BY 7 Br HC-=64 6 na nne NH₃ & Br = c. ИС, ΝΗ, aH+ Nh+HBS 1- BTS c-c%C-H I-propyne It is a syn elimination reaction in which Eck mechanism involved - Hydrogen & leaving group By are removed by strong bare Nitz by El elimination reaction : » Li + Hotech F N + LcEc-li product Reactant. i Buli is act as a strong bare which ein abstract hydrogen which is acidic in alkine molecule to from conjugate bare stabled by se hybridiration to give n-butane product. But reverse reaction is not preferable due to absent of acidic hydrogen in butane. Therefore, optian @ is correct.