Page 1018 - Advanced Organic Chemistry Part B - Reactions & Synthesis

994 CH 3
H OH
(j) H CH 2
CHAPTER 10 CH 2
Reactions Involving
Carbocations, Carbenes, CH 3 O CH CH 2 H CH 3 CH 3 O
and Radicals as Reactive CH 3
Intermediates CH 3
(l) O
(k) H
OH
H O CO 2 CH 3 O
CH 3 O
O O
CH 2 CH 2 C CH 2
H CH 3
CH 3
CH 3 CH 3
(m) (n)
O OC 2 H 5
OC 2 H 5
AcOCH 2 AcOCH 2 OCHCH 2 I O
O O
NC 2 H 5
AcO I AcO
O
AcO OAc AcO OAc R 3 SiO R 3 SiO CN
(o) O H (p)
CH 3 CH 3
CH 2 CCH 2 CO 2 H H O CH 3 O CH 3 O
O OCH 2 Ph O OCH 2 Ph
H O H
O O O
HO CH 2 CHCH 2
(q) AcOCH 2 O AcOCH 2 O O
AcO AcO
OAc AcO CH 2
(r) H
H 3 C H CH 2 OTBDMS H 3 C CH 2 OTBDMS
HO
O
O
(s)
CH 3 O
CH 3 O
N CH 3 O N
CH 3 O CH 2 CH 2 SePh
H
O O 2 CCH 3
CO 2 C 2 H 5
(t)
O CH 3
H 3 C
[ CH 3 O
CH 3 ] 2
H
CO 2 C 2 H 5 CH 3
CH 3
CH 3
HO
CH 3
CH 3

10.3. Each of the following carbenes has been predicted to have a singlet ground
state, either as the result of qualitative structural considerations or theoretical
calculations. Indicate what structural features might stabilize the singlet state in
each case.