Homework - Chapter 9 Chem 2310

Transcription

1 Homework - Chapter 9 Chem 2310 me:. ntroduction to organic halides 1. Draw a line structure for a compound with the following description: an alkyl halide with the formula C 5 H 11 a vinyl halide with the formula C 5 H 9 an allylic alkyl halide with the formula C 5 H 9 an unsaturated alkyl halide (which is not allyli with the formula C 5 H 9 e) an aryl halide with the formula C 8 H 9 f) a benzylic halide with the formula C 8 H 9 g) an aromatic halide (which is not benzyli with the formula C 8 H 9 h) a halide which is both benzylic and allylic with the formula C 9 H 9 2. Draw TW line structures for each of the following descriptions: a secondary alkyl chloride with 5 carbons a primary alkyl bromide with 4 carbons a tertiary alkyl iodide with 7 carbons a secondary alkyl fluoride with 6 carbons

2 HW Ch 9 p 2 3. Mark the following as true or false: Alkyl halides occur commonly in nature. Alkyl halides are commonly used in medicine and industry. 4. Draw the mechanism of the reaction below, including the initiation and propogation steps. Make sure to include the arrows showing how the electrons move. 2 light initiation: propagation: 5. There are four alkyl halides with the molecular formula C 4 H 9. Draw their line structures, give their common names, and match them with the partial spectra given below. no peaks between 3 and 4 ppm triplet at 3.4 ppm multiplet(6) at 3.6 ppm doublet at 3.5 ppm 1) line structure common name spectrum 2) 3) 4)

3 6. Draw arrows to depict the following: HW Ch 9 p 3 an alkyl halide acting as an electrophile in a displacement reaction: Nu an alkyl halide acting as an acid to form an alkene base an alkyl halide undergoing dissociation 7. Give the common name for the following compounds. CH 3 F 8. Give the UPAC name for each of the following alkyl halides. nclude stereochemistry where needed. F F e) f)

4 HW Ch 9 p 4 9. Draw structures for the following compounds. propyl chloride benzyl iodide vinyl bromide 2-bromo-3-ethyl-2-methylhexane e) (1R, 3R)-1,3-diiodocyclohexane. Substitution reactions of alkyl halides 10. For each of the following reactions, draw the mechanism for the type of reaction given, showing how a product would be formed. When more than one step is involved, draw the mechanism as a continuous series of reactions (as in the S N 1 example in the notes). S N 2: C N S N 1: H H S N 1: H S N 2:

5 HW Ch 9 p Circle the stronger nucleophile, and explain your reasoning. Then indicate whether each Nu will participate in S N 2 or S N 1 reactions. SH H H 12. For each reaction, write "S N 2" or "S N 1" to indicate which mechanism will be followed. K e) (CH 3 ) 3 CK

6 HW Ch 9 p What nucleophile would be required to perform the following substitution reactions using the S N 2 mechanism? Draw the arrows to show how the reaction would occur. N S e) f) N g) h) i)

7 14. Give the correct stereochemistry of the products of the following reactions. HW Ch 9 p 7 H 2 C N 15. Write the rate laws for the following reactions. Use the names of the compounds. H 2 H Eplain in you own words why the concentration of the nucleophile appears in one of the rate laws above but not the other.

8 HW Ch 9 p Draw structures for each of the following compounds. Then rank them according to which will react fastest with a strong nucleophile. (1 = fastest) cyclopenyl bromide methyl bromide 3-bromo-3-methylpentane propyl bromide methyl iodide 17. Draw structures for each of the following compounds. Then rank them according to which will react fastest with a weak nucleophile. (1=fastest) 2-iodopentane 3-bromo-3-ethylpentane 2-fluoro-2-methylpentane 3-chloropentane 1-chloropentane

9 HW Ch 9 p ndicate whether or not the following carbocations will undergo a rearrangement. f so, draw the new carbocation and an arrow showing how it was formed. e) f) 19. Draw the carbocation intermediate and all products of the following reactions. H H H H

10 20. Circle the solvent that would be best for each of the following reactions. HW Ch 9 p 10 N C acetone hexane ethanol H 2 acetonitrile water toluene ethanol hexane acetone toluene methanol N,N-dimethylformamide. Synthesis Using Substitution Reactions 21. Explain in your own words why the following syntheses would NT be effective. H 2 N C C N

11 e) F HW Ch 9 p 11 f) CH 3 CH Give the alkyl halide(s) and nucleophile(s) that would be needed to form the following products. Then analyze whether each of them would be a good way to synthesize this compound. C N