Page 692 - Advanced Organic Chemistry Part B - Reactions & Synthesis

Problems 667

PROBLEMS
(References for these problems will be found on page 1283.)

7.1. Predict the product of each of the following reactions. Be sure to consider and
specify all aspects of stereochemistry involved in the reaction.

(a) (b)
CH 3 H 2t - BuLi PhCH O benzene H 2 O
C 10 H 12 O MgBr + (CH 3 ) 2 CHCN C 10 H 18 O
H Br THF/ether/pentane, 25°C HCl
–120°C
(c) (d)
+
1) 4 equiv MeLi, 0°C H , H 2 O
CH 3 O CH 3 O CO 2 H C 9 H 10 O 2
–
1) n - BuLi 2) 10 equiv TMS Cl
C 19 H 32 O 3 Si
OSi(CH 3 ) 2 C(CH 3 ) 3
2) BrCH 2 CH C(CH 3 ) 2
CH 3 O
CH 3
(f)
(e) I Zn, TiCl 4
n - BuLi PhCO 2 CH 3 + C 10 H 12 O
C 9 H 10 CH 3 CHBr 2
TMEDA, 25°C
ICH 2 CH 2
(g) (h)
Zn dust
CH 3 (CH 2 ) 4 CH O + BrCH 2 CO 2 Et C 10 H 20 O 3 active Cd PhCOCl C 14 H 12 O
benzene CH 2 Br
(i) H NHCO 2 C(CH 3 ) 3
C + CH 2 CHCH 2 MgBr
CH O C 17 H 25 NO 3
PhCH 2
(six equiv)
7.2. Reactions of the epoxide of 1-butene with CH Li gives a 90% yield of 3-pentanol.
3
In contrast, reaction with CH MgBr under similar conditions gives an array of
3
products, as indicated below. What is the basis for the difference in reactivity of
these two organometallic compounds toward this epoxide?
O MgBr
CH 3 CH ) CHOH + CH CH CH CHCH
CH CH CH CH 2 (CH 3 2 2 3 2 2 3
3
2
5%
15% OH
CH C(CH ) + CH CH CHCH Br
+ CH 3 2 3 2 3 2 2
OH OH 63%
7%
7.3. Devise an efficient synthesis for the following organometallic compound from
the specified starting material.
(a) Li (b) (CH 3 ) 2 CLi from (CH 3 ) 2 C(OCH 3 ) 2
from O
OCH 2 OCH 3 OCH 3
(c) (d) CH 3 CH 3
CH 3 OCH 2 OCH 2 Li from Bu 3 SnCH 2 OH
H 2 C from H 2 C
Li O
(e) (f)
OSi(CH 3 ) 3
O
(CH 3 ) 3 Si H
LiCH 2 C NSi(CH 3 ) 3 from from (CH 3 ) 3 SiC CH
CH 3 CNH 2
H Li
7.4. Each of the following compounds gives a product in which one or more lithium
atoms has been introduced under the conditions specified. Predict the structure