Page 188 - Advanced Organic Chemistry Part B - Reactions & Synthesis

160 Scheme 2.17. The Wittig Reaction

CHAPTER 2 1 a + NaCH 2 S(O)CH 3
Ph 3 PCH 3 I – Ph 3 P CH 2
Reactions of Carbon DMSO
Nucleophiles with DMSO
Carbonyl Compounds O + Ph 3 P CH 2 CH 2 86%
2 b +
– n-BuLi Ph 3 P
Ph 3 PCH 2 CH 2 CH 2 CH 2 CH 3 Br CHCH 2 CH 2 CH 2 CH 3
DMSO
O
DMSO
+
CH 3 CCH 3 Ph 3 P CH(CH 2 ) 3 CH 3 (CH 3 ) 2 C CH(CH 2 ) 3 CH 3
56%
+
3 c CH 3 CH 2 PPh 3 Br – NaNH 2 CH 3 CH PPh 3
NH 3
C 6 H 5 CHO + CH 3 CH PPh 3 C 6 H 5 CH CHCH 3
benzene

98% yield, 87% Z
+
4 c CH 3 CH 2 PPh 3 I – n-BuLi CH 3 CH PPh 3
LiI
C 6 H 5 CH O + CH 3 CH PPh 3 C 6 H 5 CH CHCH 3
76% yield, 58% Z
5 d + –
Na
+ N(SiMe 3 ) 2
–
CH 3 CH 2 CH 2 CH 2 CH 2 PPh 3 Br CH 3 CH 2 CH 2 CH 2 CH PPh 3
O THF
HC(CH 2 ) 7 CH 2 OAc + CH 3 (CH 2 ) 3 CH PPh 3 CH 3 (CH 2 ) 3 CH CH(CH 2 ) 7 CH 2 OAc
79% yield, 98% Z
6 e + Cl – PhLi
C 6 H 5 CH 2 PPh 3 C 6 H 5 CH PPh 3
ether
C 6 H 5 CH O + C 6 H 5 CH PPh 3 C 6 H 5 CH CHC 6 H 5
82% yield, 70% Z
7 f
O + C 6 H 5 CH PPh 3 CHC 6 H 5
60%
8 g + – NaOH Ph 3 P stable, isolable ylide
Ph 3 PCH 2 CO 2 CH 2 CH 3 Br CHCO 2 CH 2 CH 3
H 2 O H
CHO
benzene CO 2 CH 2 CH 3
+ Ph 3 P CHCO 2 CH 2 CH 3
O OH reflux H
(2 equiv.) 2 h O OH
86%
9 f
EtOH
C 6 H 5 CHO + Ph 3 P CHCO 2 CH 2 CH 3 C 6 H 5 CH CHCO 2 CH 2 CH 3
77%, yield, only E-isomer
10 h
+ CH 3 CH 3
–
CH 3 CH 3 Ph 3 PCH 3 Br ,
KOCR 3 , toluene
56%
90°C, 30 min CH 2
O CH 3
CH 3
(Continued)