Page 952 - Advanced Organic Chemistry Part B - Reactions & Synthesis

928 Scheme 10.9. Cyclopropane Formation by Carbenoid Addition

CHAPTER 10 A. Cyclopropanes by methylene transfer
1 a
Reactions Involving Zn dust
Carbocations, Carbenes, + CH 2 I 2 CuCl
and Radicals as Reactive 24 h 92%
Intermediates OH
2 b
OH Cu–Zn H
+ CH I H
2 2
H
66%
H
3 c HO
HO CH 3
CH 3
CH I
2 2
O
O Cu–Zn 76%
O
O
OH
4 d OH
CH 3 O
CH O
3
(C H ) Zn
5 2
2
CH I
2 2
99%
CH 3
CH
3
OSEM OSEM
5 e Et Zn H
2
C H CH 2 2 I
(CH ) CO C 5 11 (CH ) CO C C 5 H 11
3 3
2
–20°C 3 3 2
OTBDMS OTBDMS
OH OH H
69%
6 f O OH O OH
CH 3 CH 3
Et 2 Zn
O CH 2 2 O
I
H O O
O H O 73%
B. Catalytic cyclopropanation by diazo compounds and metal salts
7 g 0.5 equiv
CuCN
+ N CHCO C H 5 CO 2 C 2 H 5
2
2
2
58%
8 h
CO C H
0.15 equiv 2 2 5
CH H SCF
3 CuO 3 3 CH 3
2
+N 2 CHCO C H 5
2
H CH 3 CH 3 51%
9 i
0.5 mol % CO C H
CCH ) 2 2 5
Rh(O 2 3 4
H C CHO 2 CCH + N CHCO C H
2 3 2 2 2 5
77%
O CCH 3 O
2
O CCO C H
10 j 2 2 5
(CH 3 ) 3 C CH + N CHCCO 2 C 2 H 5 Cu(acac) 2 (CH ) C
2 2 3 3
45%
k
H H
11 CH 2
Pd(O 2 CCH 3 ) 2
O + CH N 2 O
2
O O
CH
CH 3 3 96%
(Continued)