Question

Compound X has the molecular formula CsHyBr, and upon treatment with hydrogen gas and platinum metal, gives bromocyclopentane (20 points total). How many unique structures are possible candidates for the structure of compound X (1 points)? Draw all of them (6 points). Halogenation of compound X with bromine produces the following compound: Br Br r Provide the structure of compound X on the line below (3 points): Provide an efficient synthesis, showing all reagents necessary, from compound X to cyclopentane. Note that, due to constraints on bond angles, triple bonds cannot be present in five-membered rings, so you cannot propose an alkyne as an intermediate (10 points):

Answer 1

Molecular formula of compound X is CsH7Br So, DBE =C+1 - H/2 - Br/2 = 5+1 - 7/2 - 1/2 = 6 - 4= 2 Compound X provides bromocyclopentane on treatment with H/Pt So, there can be three possible structures for X as shwon below H/Pt 1-bromocyclopent-1-ene Br H/Pt Br H/Pt 3-bromocyclopent-1-ene 4-bromocyclopent-1-ene If haloogenation of X produces below trihalo compound, then compound X can have below structure Bromination Brom -Br -Br 1-bromocyclopent-1-ene