Section 19.20 Designing a Synthesis VI: Making New Carbon–Carbon Bonds 825In planning the following synthesis, the diester that is given as the starting mate-
rial suggests that you should use a Dieckmann condensation to obtain the cyclic
compound:
After the cyclopentanone ring is formed from a Dieckmann condensation of the
starting material, alkylation of the followed by hydrolysis of the ester
and decarboxylation forms the desired product.
PROBLEM 39Design a synthesis for each of the following compounds:a.b.c.d. CH 3 OCCH 2 COCH 3OOOCOHCHOCH CHCOHOO
CH 3 OCCH 2 CH 2 COCH 3OOCH 2 CH 3CCH 3OCCH 2 CH 2 CH 3Oa-carbon b-ketoCH 3 O OCH 3OOCH 3 O OCH 3- CH 3 O− CH 3 O−
- Br Br
OO O OBrCH 3 O OCH 3OOCH 3 O OCH 3−++−nucleophileelectrophileOO
OC 2 H 5 OCCH 2 CH 2 CH 2 CH 2 COC 2 H 5CH 3 CH 2O OC 2 H 5 OCnucleophilenew bond electrophile? −+C 1. C
2 H 5 O−- H+
- C 2 H 5 O− HCl, H 2 O
- CH 3 CH 2 Br
C 2 H 5 O O OC 2 H 5 OCOOCH 3 CH 2CO 2C 2 H 5 OCOO∆+ + C 2 H 5 OHOC 2 H 5 OCCH 3 CH 2