Chapter Name the following compounds: (a) 2,5-dimethyl-3-hexyne (b) 3,3-dimethyl-1-butyne (c) 2,4-octadiene-6-yne (d) 3,3-dimethyl-4-octyne (e)

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1 hapter Name the following compounds: ,5-dimethyl-3-hexyne ,3-dimethyl-1-butyne (c) 3 3 2,4-octadiene-6-yne (d) ,3-dimethyl-4-octyne (e) ,5,5-trimethyl-3-heptyne (f) 6-isopropyl-cyclodecyne 8.2 There are seven isomeric alkynes with the formula Draw and name them. 1-exyne 2-exyne

2 3-exyne 3-methyl-1-pentyne 4-methyl-1-pentyne 4-methyl-2-pentyne 3,3-dimethyl-1-butyne 8.3 What products would you expect from the following reactions? l2 3 2 l 2 l l l + 2 (c) What product would you obtain by hydration of the following alkynes?

3 hydration hydration What alkynes would you start with to prepare the following ketones? What alkyne would you start to prepare each of the following compounds by a hydroboration / oxidation reaction? ow would you prepare the following carbonyl compounds starting from an alkyne?

4 solution: gs 4, 3 1.B / Na 8.8 Using any alkyne needed, how would you prepare the following alkenes? trans-2-ctene cis-3-eptene (c) 3-Methyl-1-pentene solution: Li,N 3 2 Lindlar catalyst (c) 2 Lindlar catalyst 8.9 Propose structures for alkynes that give the following products on oxidative cleavage by KMn 4 : 2 + 2

5 2 3 ( 2 ) ( 2 ) 7 2 The structure is: 3 ( 2 ) 7 ( 2 ) 7 ( 2 ) The pk a of acetone, 3 3, is Which of the following bases is strong enough to deprotonate acetone? K (pk a of 2 = 15.7) Na + - (pk a of 2 2 = 25) (c) Na 3 (pk a of 2 3 = 6.4) (d) Na3 (pk a of 3 = 15.6) Because pk a ( 2 2 ) > pk a ( 3 3 ) 8.11 Show the terminal alkyne and alkyl halide from which the following products can be obtained. If two routes look feasible, list both. Answer: (c) 8.12 ow would you prepare cis-2-butene starting from propyne, an alkyl halide, and any other reagents needed? This problem can t be worked in a single step. You ll have to carry out more than one

6 reaction. Answer: 3 NaN2 N3 3 TF Lindar catalyst Beginning with 4-octyne as your only source of carbon and using any inorganic reagents necessary, how would you synthesize the following compounds? Butanoic acid cis-4-ctene (c) 4-omooctane (d) 4-ctanol (4-hydroxyoctane) (e) 4,5-Dichlorooctane KMn Lindler catalyst (c) 2 Lindler catalyst, ether (d)

7 2 Lindler catalyst 1.BF 3, TF , - (e) 2 Lindler catalyst X 2 2 l 2 l l 8.14 Beginning with acetylene and any alkyl halides needed, how would you synthesize the following compounds? Decane 2,2-Dimethylhexane (c) exanal (d) 2-eptanone NaN 2 Na Pd/

8 NaN 2 Na ( 3 ) Pd/ (c) NaN 2 Na B (d) NaN 2 Na S 4, 2 gs Name the following alkynes, and predict the products of their reaction with (i) 2 in the presence of a Lindlar catalyst and (ii) 3 + in the presence of gs 4:

9 2 / Lindlar at gs 4 / / Lindlar at gs 4 / From what alkyne might each of the following substances have been made? 3 3 l l is from Methyl-pentyne and is from Ethynyl-2-methyl-cyclohexane 8.17 ow would you prepare the following substances, starting from any compounds having four carbons or fewer?

10 3 2 2 Zn(u) Ether S 4, 2 gs The following cycloalkyne is too unstable to exist. Explain It s not possible to form a small ring containing a triple bond because the angle strain that would result from bending the bonds of an SP-hybridized carbon to form a small ring is too great Give IUPA names for the following compounds a. 3 b c. 3 3

11 3 2 d. 3 e f a. 2,2-Dimethyl-3-hexyne b. 2,5-ctadiyne c. 3,6-Dimethyl-2-heptene-4-yne d. 3,3-Dimethyl-1,5-hexadiyne e. 1,3-exadiene-5-yne f. 3,6-Diethyl-2-methyl-4-octyne 8.20 Draw structures corresponding to the following names: a. 3,3-Dimethyl-4-octyne b. 3-Ethyl-5-methyl-1,6,8-decatriyne c. 2,2,5,5-Tetramethyl-3-hexyne d. 3,4-Dimethylcyclodecyne e. 3,5-eptadien-1-yne f. 3-hloro-4,4-dimethyl-1-nonen-6-yne g. 3-sec-Butyl-1-heptyne h. 5-tert-Butyl-2-methyl-3-octyne a. 3,3-Dimethyl-4-octyne

12 b. 3-Ethyl-5-methyl-1,6,8-decatriyne c. 3,6-Dimethyl-2-heptene-4-yne d. 3,4-Dimethylcyclodecyne e. 3,5-eptadien-1-yne f. l 3-hloro-4,4-dimethyl-1-nonen-6-yne g. 3-sec-Butyl-1-heptyne

13 h. 5-tert-Butyl-2-methyl-3-octyne 8.21 The following two hydrocarbons have been isolated from various plants in the sunflower family. Name them according to IUPA rules SLUTIN: (3E, 5E, 11E)-1,3,5,11-Tridecatetraen-7, 9-diyne. 1-Tridecene-3, 5, 7, 9, 11-pentayne Predict the products of the following reactions. 2, Pd/ A 2/Lindlar B SLUTIN: A: B:

14 A hydrocarbon of unknown structure has the formula 810. n catalytic hydrogenation over the Lindlar catalyst, 1 equivalent of 2 is absorbed. n hydrogenation over a palladium catalyst, 3 equivalents of 2 are absorbed. a) ow many degrees of unsaturation are present in the unknown? b) ow many triple bonds are present? c) ow many double bonds are present? d) ow many rings are present? e) Draw a structure that fits the data. a) 4 degrees of unsaturation are present. b) 1 triple bond is present. c) 1 double bond is present. d) 1 ring is present. e) The possible structure can be: etc Predict the products from reaction of 1-hexyne with the following reagents: a) 1 equiv b) 1 equiv l2 c) 2, Lindlare catalyst d) NaN2, in N3, the 3 e) 2, 2S4, gs4 f)2 equiv l l a) 1-hexyne l l2 l b) 1-hexyne l 2 Lindlar atalyst c) 1-hexyne d) 1-hexyne NaN2 N3 Na 3

15 2S4,2 e) 1-hexyne gs4 l 2l f) 1-hexyne l 8.25 Predict the products from reaction of 5-decyne with the following reagents: 2, Lindlar catalyst. Li in N 3. (c) 1 equiv 2. (d) B 3 in TF, then 2 2, -. (e) 2, 2 S 4, gs 4. (f) Excess 2, Pd/ catalyst (c) 4 9. (d) (e) 4 9. (f) Predict the products from reaction of 2-hexyne with following reagents: 2 equiv 2. 1 equiv. (c) Excess. (d) Li in N 3. (e) 2, 2 S 4, gs etc (c) and (d) 3 7. (e) 3 7 and Predict the products of the following reactions: B 3,TF NaN2,N 3

16 (c) 3 NaN 2,N ydrocarbon A has the formula 9 12 and absorbs 3 equivalents of to yield B, 9 18,when hydrogenated over a Pd/ catalyst. n treatment of A with aqueous 2S 4 in the presence of mercury(ii), two isomeric ketones, and D, are produced. xidation of A with KMn 4 gives a mixture of acetic acid ( 3 2 ) and the tricarboxylic acid E. Propose structure for compounds A-D, and write the reactions. A B D 2 3 E (1) Pd/ (2) mercury(ii) S (3) 2 3 KMn ow would you carry out the following reactions?

17 3 2 2 S 4, 2 gs , B , 2 2 (c) 3 NaN 2 3 (d) 3 2 Lindlar catalyst 3 KMn (e) (f) K, ethanol 8.30 ccasionally, chemists need to invert the stereochemistry of an alkene, that is, to convert a cis alkene to trans alkene, or vice versa. There is no one-step method for doing an alkene inversion, but the transformation can be carried out by combining several reactions in the proper sequence. ow would you carry out the following reactions? trans-5-decene K, ethanol cis-5-decene 3. 2, Lindlar catalyst cis-5-decene 1. 2 trans-5-decene 2. K, ethanol 3. Li, N Propose structures for hydrocarbons that give the following products on oxidative cleavage by Kmn 4 or ( 2 )

18 (c) 2 ( 2 ) 8 2 (d) (e) (c) (d) (e) 8.32 Each of the following syntheses requires more than one step. ow would you carry them out? (B) 2 3 ( 3 ) 2 2 ( 3 ) Lindlar catalyst 2. Zn/ 3

19 NaN 2 ( 3 ) 2 2 ( 3 ) 2 2 Na Li ( 3 ) N 3 ( 3 ) ow would you carry out the following transformation? More than one step is needed ow could you carry out the follow conversion? More than one step is needed.? B 3 P 2 2 / - 2 l ow would you carry out the following transformation? More than one step is needed.

20 2 2 l 2 K Ethenal KN 2 K 3 Li N Synthesize the following compounds using 1-butyne as the only source of carbon, along with any inorganic reagents you need. More than one step may be needed. 1, 1, 2, 2-Tetrachlorobutane l l l l 2 2 l 2 l l 2 3 1, 1-Dichloro-2-ethylcyclopropane l l l Lindlar catalyst 2 3 l 3 K l l (c) Butanal

21 2 3 2 Lindlar catalyst 1. B 3, TF , ow would you synthesize the following compounds from Acetylene and any alkyl halides with four or fewer carbons? More than one step may be required (c) ( 3 ) (d) (e) NaN 2 N 3 Na TF NaN 2 N 3 Na NaN 2 TF N Na 3 2 TF (c) NaN 2 ( 3 ) 2 2 Na (3 ) ( N ) Lindlar catalyst (d) NaN 2 Na N 2 2 NaN 2 3 TF N Na TF S 4, gs 4 (e) NaN 2 N 3 Na B 3 TF ow would you carry out the following reactions to introduce deuterium into organic molecules? D D ? ? D D (c)? D (d)

22 ? D D 2 D Lindlar catalyst D 2 5 D Li,ND 3 D D Na + N 2 - N Na + D D Na + N 2 - D 2 D D 2 D D 2 N 3 Lindlar catalyst 8.39 ow would you prepare cyclodecyne starting from acetylene and any alkyl halide needed? + 2 NaN 2 N 3 Na Na + I I TF 8.40 The sex attractant given off by the common housefly is an alkene named muscalure. Propose a synthesis of muscalure starting from acetylene and any alkyl halides needed. What is the IUPA name for muscalure? cis- 3 ( 2 ) 7 ( 2 ) 12 3 The IUPA name for muscalure is cis-9-tricosene.

23 NaN 2 3 ( 2 ) 7 3 ( 2 ) 7 NaN 2 3 ( 2 ) 12 3 ( 2 ) 7 ( 2 ) Lindlar 3 ( 2 ) 7 ( 2 ) ompound A ( 9 12 ) absorbed 3 equivalents of on catalytic reduction over a palladium catalyst to give B ( 9 18 ). n ozonolysis, compound A gave, among other things, a ketone that was identified as cyclohexanone. n treatment with, gave ( 10 14).Give the structure of A, B,. A: B: : 8.42 ydrocarbon A has the formula 128. It absorbs 8 equivalents of 2 on catalytic reduction over a palladium catalyst. n ozonolysis, only two products are formed: oxalic acid (22) and succinic acid (2222). Write the reactions, and propose a structure for A. Slution:

24 8 2 Pd/ cyclododecane Identify the reagents a-c in the following scheme: a b c ` 1. NaN 2, N / Lindlar at 2 I 2 / Zn(u) 8.44 rganometallic reagents such as sodium acetylide undergo an addition reaction with ketones, give alcohols: 1. Na R R R R ow might you use this reaction to prepare 2-methyl-1,3-butadiene, the starting material used in the manufacture of synthetic rubber

25 1. Na + 2 S 4, TF 2 Lindlar catalyst 8.45 Erythrogenic acid, 18262, is an acetylenic fatty acid that turns a vivid red on exposure to light. n catalytic hydrogenation over a palladium catalyst, 5 equivalents of 2 are absorbed, and stearic acid, 3(2)162, is produced. zonolysis of erythrogenic acid gives four products: formaldehyde, 2; oxalic acid, 22; azelaic acid, 2 (2)72; and the aldehyde acid (2)42. Draw two possible structures for erythrogenic acid, and suggest a way to tell them apart by carrying out some simple reactions. Solution The problem can be described as following illustration: Zn And first we can predict the unsaturated degree of starting material by the fact that it can absorb 5 2 and form a carboxylic acid. So The molecular has 5 double bonds or 1 triple bond and 3 double bonds or 2 triple bonds and 1 double bond besides a = bond, and there is no rings in the molecular. Second we can think about the products after it is treated with 3,and we can get the solultion t the problem.

26 You can see two possible starting materials according to the problem exactly. owever, we can tell them apart from each other by following method. STEP1 Treat the SM with Lindlar catalyst, and then we can get the product only contains double bond but no triple bond. STEP2 Treat the product get from the step with 3,3+ and Zn and then we can get the products following. STEP3 Analyze the products and you can find the differences written following between the different SMs. At last we can tell them apart easily Zn

27 Zn Terminal alkynes react with 2 and water to yield bromo ketones. For example: 2, 2 2 Propose a mechanism for the reaction. To what reaction of alkenes is the process analogous? rearrangement The mechanism here is just like the halohydrin of alkene A cumulene is a compound with three adjacent double bonds. Draw an orbital picture of cumulene. What kind of hydridization do the two central carbon atoms have? What is the geometric relationship of the substituents on one end to the substituents on the other end? What kind of isomerism

28 is possible? R 2 R 2 They are sp hybridized. R R R R The geometric relationship of the substituents on one end to the substituents on the other end is cis and trans. (c) Stereoisomers Reaction of acetone with D3+ yields hexadeuterioacetone. This is, all the hydrogens in acetone are exchanged for deuterium. Review the mechanism of alkyne hydration, and then propose a mechanism for this deuterium incorporation. D Acetone D 3 D 3 exadeuterioacetone D D D 3 D3