In a series of seven steps, (S)-malic acid is converted to
Chapter 18, Problem 18.48(choose chapter or problem)
In a series of seven steps, (S)-malic acid is converted to the bromoepoxide shown on the right in 50% overall yield. This synthesis is enantioselectiveof the stereoisomers possible for the bromoepoxide, only one is formed. OH HOOC COOH A (C8H14O5) C (C9H18O4 B ) F (C4H8OBr2) O D E Br 1.CH3CH2OH, H1 4.TsCl, pyridine 2. 3.LiAlH4, then H2O 5.NaBr, DMSO 6. H2O, CH3COOH 7.KOH , H1 O Steps/reagents: (S)-Malic acid A bromoepoxide 1 2 5 6 7 3 4 In thinking about the chemistry of these steps, you will want to review the use of dihydropyran as an !OH protecting group (Section 16.7D) and the use the p- toluenesulfonyl chloride to convert the !OH, a poor leaving group, into a tosylate, a good leaving group (Section 10.5D). (a) Propose structural formulas for intermediates A through F, and specify the confi guration at each chiral center. (b) What is the confi guration of the chiral center in the bromoepoxide? How do you account for the stereoselectivity of this seven-step conversion?
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer