Ch 19 answers - 1 Answers to Ch. 19 Extra problems 1. Show...

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1 Answers to Ch. 19 Extra problems 1. Show the major product (or products if more than one will be formed in significant amount) for the following reactions: H O S S H SH SH This is just a thioacetal formation, but in Ch 19 we learned that the deprotonated material is an acyl anion equivalent H + a. O O O H CH 3 _ The acidic proton is lost rapidly compared to retro-Claisen, and the anion does not do it because it is protected from EtO - addition to the ketone carbonyl group O O O CH 3 NaOEt EtOH + EtOH b. retro-Claisen occurs when there is no acidic proton betwen the CO groups that EtO - can remove, so EtO - can add to the ketone carbonyl group, which is the first step in retro-Claisen O O O H 3 C CH 3 OEt O O O H 3 C CH 3 H NaOEt EtOH c. 2. H 3 O + 1. N O O O N O _ + (during 1) 2. H 3 O + d. * * (closes at the *'d atoms to neutralize charge) 1. NaOEt 2. O H O Br O C H 2 H O H e. 1. 2 eq. of NaOEt 2. is an intermediate. O O Br Br O O O O H Br f. It deprotonates and does an internal S N 2, closing the 3-membered ring. Remember to count the carbons correctly in rings formed by double alkylation of β -dicarbonyl compounds, without forgetting the one that comes from the enolate carbon
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2 2. Show regents and any intermediate compounds which would be isolated for the following conversion. Any reagents stable enough to buy may be used. SH SH 1. BuLi 2. PhCH 2 Br H 2 O,MeOH H O Mg metal O acetone S S H or many others (Jones) CrO 3 , H 2 SO 4 S S HO H H + HgCl 2 PhCH 2 MgBr, PhCH 2 Br Et 2 O a. OR 2. H 2 C=CH-CH 2 Br 1. EtONa 3. EtONa (can alkylate 4. PrBr in either order) H 3 O + , H 2 O heat EtOH, HCl (or other esterification method_ O O OEt OEt CO 2 Et O O OEt OEt CO 2 H b. EtO
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This note was uploaded on 02/14/2011 for the course ORGANIC CH 341 taught by Professor Idk during the Spring '11 term at University of Wisconsin.

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Ch 19 answers - 1 Answers to Ch. 19 Extra problems 1. Show...

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