Question

Regioselectivity of E1 and E2 Reactions 3. The reaction between a 1,2-dimethylcyclohexanol and concentrated strong acid results in an El reaction. a. Show the first step in this reaction (consider that the acid catalyst can protonate the OH group which eventually can form H,O that can act as a good leaving group). CASH OH conc.H2SO4 CH b. What is the geometry at the reaction center of the intermediate? C. Show the final step and all possible alkene products. d. State the rule that determines the major and minor alkene product(s) that form during elimination reactions. e. Using the rule from part de determine the major and minor products.

Answer 1

3) a) Given alcohol is a tert. alcohol. Hence first step is the protonation of the hydroxyl group and cleavage of that protonated hydroxyl group as a water molecule leading to tert. carbocation CH3 CH3 Нас H3C CHз OH H+ Нас Hас. Hас. b) The carbocation is a sp2 hybridized atom and hence it has trigonal planar geometry Minor Major CHз Нас Нас. CH3 CH2 Hас Нас. c) Нас Нас. 1,6,6-trimethylcycl 1,1-dimethyl-2-methy ohex-1-ene lidenecyclohexane There is two types of alpha proton present and hence it can give two products d) Using Zaitsev's rule we can predict the major alkene product. IT states that the most substituted alkene product will be the most stable, and hence it will be the major product. e) 1,6,6-trimethylcyclohex-1-ene is the most substituted alkene and hence it is the major product