2 xs HX 1 X 1) xs NaNH2 2) H₂O R R 3 4 5 -CH3 R R H HgSO4 H2SO4, H₂O 1) R₂BH HX X2 (one equiv.) 2) H2O2, NaOH X R CCl4 6 R X X 1 X R 2) H₂O 1) xs NaNH2 XS X2 X X 1) NaNH2 2) RX 1) O3 2) H₂O CCl4 X R 7 9 8 H2 12 R R R R Lindlar's cat. + R OH O=C=0 H₂ Na R R 10 11 R Pt NH3 (1) R 2. Fill in the reagents for the synthesis shown below A В A: B: C: ABC HO

reaction by filling in any Starting materials, reagents or products as needed.

Acid-catalyzed hydrolysis of the following epoxide gives a trans diol. Of the two possible trans diols, only one is formed. How do you account for this stereoselectivity?

Identify the missing reagents a-f in the following scheme:

A step in a synthesis of PGE1 (prostaglandin E1, alprostadil) is the reaction of a trisubstituted cyclohexene with bromine to form a bromolactone. Propose a mechanism for formation of this bromolactone and account for the observed stereochemistry of each substituent on the cyclohexane ring. Alprostadil is used as a temporary therapy for infants born with congenital heart defects that restrict pulmonary blood flow. It brings about dilation of the ductus arteriosus, which in turn increases blood flow in the lungs and blood oxygenation.

Identify the reagents represented by the letters a-e in the following scheme:

Nicotinic acid, more commonly named niacin, is one of the B vitamins. Show how nicotinic acid can be converted to (a) ethyl nicotinate and then to (b) nicotinamide.

Tamoxifen is a drug used in the treatment of breast cancer. How would you prepare tamoxifen from benzene, the following ketone, and any other reagents needed?

Show how the synthetic scheme developed in Problem 23.67 can be modified to synthesize this triiodobenzoic acid X-ray contrast agent.

3. Provide a mechanism for the following reaction. OMe a) MeLi (2 equiv) b) H3O+ HO Me Me