11/8/19 The cis- and trans-isomers of 1-bromo-2-methylcyclohexane are shown below. One of these isomers undergoes E2...
6. Predict which of the following two isomers (cis- or trans-) will undergo an E2 elimination under the treatment with EtoNa in EtOH more rapidly. A) For the explanation of the reaction rate, draw chair conformations for each isomer, determine which conformation is more stable . B) Draw the major product and the mechanism of the reactions. CI cis-isomer trans-isomer
(a) When cis-1-bromo-2-methylcyclohexane undergoes an E2 reaction, two products (cycloalkenes) are formed. What are these two cycloalkenes, and which would you expect to be the major product? Write conformational structures showing how each is formed. (b) When trans-1-bromo-2-methylcyclohexane reacts in an E2 reaction, only one cyclo- alkene is formed. What is this product? Write conformational structures showing why it is the only product.
In each of the cases below, which isomer is more stable? a) 1,4-dimethylcyclohexane (cis/trans?): b) 1-bromo-2-methylcyclohexane : (cis/trans?) c) 1,3-diethylcyclohexane (cis/trans?)
cis-1-bromo-4-tert-butylcyclohexane and trans-1-bromo-4-tert-butylcyclohexane both react with sodium ethoxide in ethanol to give 4-tert-butylcyclohexene. However, one of the isomers reacts much more rapidly than the other isomer. Predict which isomer is reacting faster by showing a mechanism for each isomer. Your answer should account for the slower reacting substrate.
8. Explain why the following deuterated 1-bromo-2-methylcyclohexane undergoes dehydrohalogenation by the E2 mechanism to give only the indicated product. Two other alkenes are not observed CH3 (CH, Br OCH, -CH Сн, H DH DH not observed observed
4. The reaction between cis-1-bromo-2-methylcyclohexane and ethoxide (a very strong base) results in an E2 reaction. (refer to Mechanism 9.8 in your textbook) a. Show the transition state for this reaction. CHE + CH, CH, CH, OH b. Show the formation of the product(s) from the transition state. c. Use the rule from part 3d, to determine the major and minor alkene products.
Prelab Assignment Prior to the laboratory, complete the following Pre-lab Question(s): 1. Cis and Trans isomers of 1,2-dichlorocyclohexane, 1,3-dichlorocyclohexane and 1,4- dichlorocyclohexane - Draw the perspective, Chair and mirror image (if applicable) of each isomer. Perspective (Wedge dash) Chair conformation Drawing Mirror Image chair Chiral? Cis-1,2-dichlorowyclohexane Trans-1.2-dichlorocyclone Is either isomer a mese compound? If yes, draw the plane of symmetry on the mese compound What is the errochemical relationship between these is transiomer? C-1,3-dichlorocyclohexane Trans-1,3-dichloroceae Is either somer amese compound?...
4. Why does the reaction of trans-1-bromo-2-methylcyclohexane yield the non-Zaitsev elimination product 3-methylcyclohexene on treatment with a base? Draw structures in chair conformations to support your explanation. сн, сн, КОН Br
I really meed help with #2 & #3 Questions Module BCCL 150 W 1. Draw one cis and one trans-1-chloro-3-methylcyclohexane with the cyclohexane in the of the paper and bold and dashed groups (there are actually 2 of each). Look at ang w the four possible chair conformers of these two compounds and their calculated energies in 3D. Table 3. Conformational Isomers of 1-chloro-3-methylcyclohexane Compound Cis (chair) Cis (chair) flipped Draw w/bold/dashed Draw ay in plane of page Draw axin...
Question 6 - 10 pts. Homework • Unanswered When (cis)-1-bromo-2-methylcyclohexane is treated with methanol and heat, four different products are formed -- two by substitution (1-methoxy-2- methylcyclohexane and 1-methoxy-1-methylcyclohexane) and two by elimination (1-methylcyclohexene and methylidene cyclohexane (you will have to look that one up!)). What conditions could be used to change the outcome of this reaction by promoting the production of 3-methylcyclohexene as the product? [] Fulls