Page 575 - Advanced Organic Chemistry Part B - Reactions & Synthesis

Scheme 6.10. Photocycloadditions of Enones with Alkenes and Alkynes 549

A. Intrermolecular additions SECTION 6.3
N
1 a [2 + 2] Cycloadditions
C
C N h ν and Related Reactions
+ H 2 C CH 2 Leading to Cyclobutanes
O O 62%
2 b h ν
+ H 2 C CH 2
–80°
O 50%
3 c O
O O O
H H H H
CH 3 CH 3 CH 3
+ h ν +
benzene
CH(CH 3 ) 2
(CH 3 ) 2 CH H (CH 3 ) 2 CH H
60% 30%
4 d
hν
+
CH 2 Cl 2
CO 2 CH 3 CO 2 CH 3 67%
5 e O O
h ν CH 3
O + CH 3 CH 2 C CCH 3 O
Ph 2 CO
O CH 3 CH 2 79%
O
6 f O H O
H Cl
Cl
CH 3 h ν CH 3
+
Cl
CH 3 CH 3 Cl
H CO 2 CH 3 H
CO 2 CH 3
95%
7 g
H O CH 3 H O
CH 3
h ν
+ CH 2 CH 2 H
–78°C
H CH 3 H
CH 3
B. Intramolecular Additions
O
O
8 h OCCH 3 h ν OCCH 3
cyclohexane
C
78%
O
O
9 i
O O
h ν CH 3
CH 3
CH 2
hexane
CH 3
CH 2 CH 2 CH 2 CCH 3
77%
CH 3
H 3 C
(Continued)