UNIVERSITI MALAYA UNIVERSITY F MALAYA PEPERIKSAAN IJAZA SARJANA MUDA SAINS EXAMINATIN FR TE DEGREE F BACELR F SCIENCE PEPERIKSAAN IJAZA SARJANA MUDA SAINS DENGAN PENDIDIKAN EXAMINATIN FR TE DEGREE F BACELR F SCIENCE WIT EDUCATIN SESI AKADEMIK 2009/2010 : SEMESTER 2 ACADEMIC SESSIN 2009/2010 : SEMESTER 2 SCES3120/SCEP3120 : Kimiarganik III rganic Chemistry III April/Mei 2010 April/May 2010 Masa : 2 jam Time : 2 hours ARAAN KEPADA CALN INSTRUCTINS T CANDIDATES : Jawab SEMUA soalan. Answer ALL questions. (Kertas soalan ini mengandungi 5 soalan dalam 8 halaman yang dicetak) (This question paper consists of 5 questions on 8 printed pages)
SCES3120/SCEP3120/02 BAAGIAN/SECTIN A (33 markah/marks) JAWAB SEMUA SALAN ANSWER ALL QUESTINS 1. Beri penjelasan pembentukan hasil di bawah. Beri mekanisme di mana perlu. Give an explanation for the formation of the products below. Give mechanism where necessary. i. LDA, TF ii. C 3 C 2 I i. N 3 +, ii. C 3 C 2 I iii. 3 + 2. (i) Lukis struktur enolat A dan B ( A dan B adalah stereiosomer) yang terbentuk dalam tindak balas di bawah. Nyatakan stereoisomer utama (A) yang terbentuk dan jelaskan jawapan anda.. Draw the structure of the enolates A and B ( A and B are stereoisomers) formed in the reaction below. Indicate the major stereoisomer (A) and explain your answer. C 3 C 3 LTMP -78 oc A + B Cadangkan hasil yang terbentuk apabila A bertindak balas dengan etanal. Nyatakan stereokimia yang terlibat. Suggest the product formed when A reacts with ethanal. Indicate the stereochemistry involved. (3 markah/marks) SCES3120/SCEP3120/03
3. Tunjukkan semua analisis retrosintesis, reagen terlibat serta keadaan tindak balas yang dicadangkan dalam sintesis ini. Show the full retrosynthetic analysis and indicate the reagents and reaction conditions planned for the synthesis. Jawab soalan 4(a) dan mana-mana dua (2) soalan dari bahagian 4(b), 4(c) dan 4(d). Answer question 4(a) and any two (2) from parts 4(b), 4(c) and 4(d). 4. (a) Tindak balas 2-butanone dengan hidrogen dalam kehadiran mangkin paladium menghasilkan campuran hasil A dan B. The reaction of butanone with hydrogen in the presence of palladium catalysts give a mixture of products, A and B. C 3 C 2 C C 3 2 Ni A + B (i) (iii) (iv) Beri struktur A dan B, nyatakan stereokimia dengan jelas, dan tentukan konfigurasi Cahn-Ingold-Prelog bagi setiap pusat stereo A dan B. Provide the structure of A and B, clearly indicating stereochemistry, and assign the Cahn-Ingold-Prelog configuration to each stereocentre of A and B. Nyatakan sama ada setiap hasil adalah sebatian kiral atau tak kiral. Indicate whether each product is a chiral or an achiral compound. Apakah perkaitan isomer antara hasil A dan B (iaitu isomer kedudukan, enantiomer atau diastereomer). What is the isomeric relationship between the products A and B (i.e constitutional isomers, enantiomers or diastereomers) Adakah anda jangka hasil yang terbentuk mempunyai peratusan yang sama atau tidak sama? Jelaskan jawapan anda menggunakan gambaran yang jelas dan informatif. Do you expect the products to be formed in equal or unequal percentage? Explain your answer using clear and informative drawings. (13 markah/marks) SCES3120/SCEP3120/04
(b) Kelaskan setiap yang berikut sebagai meso, akiral, atau kiral. Lukis kedua-dua enantiomer bagi sebatian kiral: Classify each of the following as meso, achiral, or chiral. Draw both enantiomers of the chiral compounds: Br Br i) C C ii) C 3 C 2 C 3 C 3 C 3 iii) C C C C C iv) N 2 Me C v) Me Me (c) (i) Dengan memberi contoh yang sesuai jelaskan istilah berikut: By giving the appropriate examples explain the following terms: - Sintesis perkongsian kiral - Chiral pool synthesis - Sintesis bantuan kiral - Chiral auxiliary synthesis Lengkapkan tindakbalas berikut: Complete the following reaction B 3 /TF 2 2 / - C + D i) Ipc 2 B ii) 2 2 / - E (98% ee) SCES3120/SCEP3120/05
(d) Beri reagen atau hasil F hingga I dalam skema berikut untuk sintesis stereopilihan enol eter. Cadangkan perantaraan bagi pembentukan dan I. Give reagents or products F to I in the scheme below for the stereoselective synthesis of enol ether. Propose the intermediates for the formation of and I. Boc C 3 N CN Na, MeI DMF F G Boc C 3 N C 3 C Na, TBSCl TF + I Jawab soalan 5(a) dan mana-mana dua (2) dari bahagian 5(b), 5(c) dan 5(d). Answer question 5(a) and any two(2) from parts 5(b), 5(c) and 5(d). 5. (a) (i) Dengan menggunakan konformasi cisoid lukis empat (4) M (ψ 1, ψ 2, ψ 3 dan ψ 4 ) yang diterbitkan dari p A bagi 1,3-butadiene. By using the cisoid conformation draw the four (4) Ms ((ψ 1, ψ 2, ψ 3 and ψ 4 ) arising from the p As in 1,3-butadiene. Tunjukkan struktur hasil dalam tindak balas elektrosiklik berikut. Show the structure of product(s) in the following electrocyclic reaction C 3 C 3? C 3 C 3 h? Berikan penerangan mekanisme bagi pembentukan hasil dalam tindak balas di atas. Give the mechanistic explanation for the formation of product(s) in the above reaction. (14 markah/marks) SCES3120/SCEP3120/06
(b) Takrifkan Kesan Isotop Kinetik Primer. Cadangkan penerangan mekanisme bagi nilai k /k D = 1 bagi tindakbalas penukargantian aromatik berikut. Define Primary Kinetic Isotope Effect. Propose the mechanistic explanation of the value of k /k D = 1 for the following aromatic substitution reactions. N 2 + + N 2 + + D N 2 + + N 2 + D + bserved k /k D = 1.0 (c) Tindakbalas berikut menunjukkan pembentukan tert-butil klorida dari tertbutil alkohol dan hidrogen klorida. The following reaction shows the formation of tert-butyl chloride from tertbutyl alcohol and hydrogen chloride. (C 3 ) 3 C + Cl (C 3 ) 3 Cl + 2 Cadangkan mekanisme tindak balas di atas dan lukis gambarajah Tenaga Keupayaan- Koordinat Tindakbalas untuk tindak balas tert-butil alkohol dan hidrogen klorida. Propose the mechanism for the reaction and draw the Potential Energy Reaction Coordinate diagram for the reaction of tert-butyl alcohol and hydrogen chloride. ATAU/R Berikan penerangan mekanisme untuk nilai yang diperhatikan bagi pemalar tindakbalas ammett, ρ bagi tindakbalas berikut: Give the mechanistic explanation for the observed value of ammett reaction constant, ρ, for the following reaction: _ X + C 3 C 2 C 2 I k ethanol, 25 o C Product ρ= -0.99 X= substituent SCES3120/SCEP3120/07
(d) ( i) pk a bagi asid p-metoksibenzoik ialah 4.49 pada 25 o C dan pk a bagi asid benzoik ialah 4.19 pada 25 o C. itung nilai σ bagi p-me. The pk a of p-methoxybenzoic acid is 4.49 at 25 o C and the pka of benzoic acid is 4.19 at 25 o C. Calculate the value of σ for p-me. (5 markah/marks) C 2 Et C 2 _ + - k x + Et X m = + 0.71 p-me = - 0.27 Apabila X = m-n 2, nilai k m-n2 / k = 63.5, hitung nilai k m-n2 / k apabila X = p-me. When X = m-n 2, the value of k m-n2 / k = 63.5, calculate the value of k m-n2 / k when X = p-me. (5 markah/marks)
SCES3120/SCEP3120/08 Lampiran(Appendix) LTMP NLi Ipc 2 B d-ipc.9-bbn diisopinocamphenylborane deutrated Isopinocamphenyl-9-borabicyclo[3.3.1]nonane (R)-BINAL- S-BINAP-Rh(1) TBSCl tert-butyldimethyl silyl chloride (t-bume 2 SiCl) Boc t-butoxycarbonyl ) 2 B C Boc Bu-t Ipc 2 B Ph 2 P Rh + P Ph 2 Me Me Al Et (S)-BINAP-Rh + complex (R)-BINAL- ***************************