Page 569 - Advanced Organic Chemistry Part B - Reactions & Synthesis

Scheme 6.8. [2 + 2] Cycloadditions of Ketenes 543

CH SECTION 6.3
1 a 3
70°C CH
+ (CH 3 ) 2 C C O 3 [2 + 2] Cycloadditions
and Related Reactions
O 77% Leading to Cyclobutanes
2 b O
CH + CH CHCCl Et N O
3
3
2
60°C
Cl CH 3 Cl 60%
H H
3 c O Et N O O
3
+ CH 3 CHCCl 0– 5°C +
Cl CH3
Cl H CH 3 H Cl 14%
4 d SiO 63%
R 3 SiO R 3
CH 3 O CH 3 O
Et N
CHCCl 3
+ Cl 2
Cl
H CH 3 H CH 3 Cl
5 e CH
CH CH(CH 2 2 3 CH 3
)
2
N Cl
(C H ) N
2 5 3
O
CO H 35 – 47%
2
6 f CH
CH 3 2 O
CH 3 CH 3
Cl
(i Pr) NEt CH 3 CH 2
2
105°C
O 43%
CH CH 3 O
H
CH 3 CH 3 Cl CH 3 CH 3 O
7 g
CH 2 Et N
3
25°C
(CH ) CH H (CH ) CH H 80%
3 2
3 2
H
8 h O O O
3
CH 2 Et N
O
Cl 80°C
72%
CH 3 CH 3
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