Page 589 - Advanced Organic Chemistry Part B - Reactions & Synthesis

Scheme 6.14. Claisen Rearrangements of Allyl Vinyl Ethers and Related 563
Compounds
SECTION 6.4
a
1 CH 2 CH O [3,3]-Sigmatropic
195°C
Rearrangements
87%
OCH CH 2
2 b
CH 3 O
H +
(CH 3 ) 2 CCH CH 2 + H 2 C (CH 3 ) 2 C
COCH 3 125°C
CHCH 2 CH 2 CCH 3
HO 94%
c
3 CH 3 CH 3 O
110°C
CC CCCH 2 CH 2 C
CCHCH 2 CH 3 + CH 2 CH 2 CH 2 CHCH 2 CH 3
CH 2 +
H
~70%
OH OCH 3 CH 3 CH 3
d
4 CH 3 O
O
140–145°C CH 3
O O
CH 3
CH 3 CH 2
CH 3
61%
5 e
O O CH 3 CH 3
CH 3
CH 3 CH 3 CH 2 CH 2 CH 2 CN
CH 2 CHOC 2 H 5
CH 2 CH 2 CH 2 CN 200°C
CH 3 CH 3 CH 2 CH 2 CH 2 CN
CH 2
CH 2 OH CH 2 OCH CH 2 95%
Hg(O 2 CF 3 ) 2 73% CH 2 CH O
6 f O CH 3
H
OCH 3
CH 2
PdCl 2
+
HO
CH 3 r.t. 10 h 78%
OCH 3
7 g CH 3
(i-Bu) 3 Al CH 3
OH CH 2 CCH 3
CH 3
CH 3 OH
0°C CH 3
CH 2 89%
POCl 3
CH 3 CH 3
h
8
TBDMSO OMOM OH CH 2 CHOC(CH 3 ) 3 TBDMSO
excess OMOM
CH 2 CH O
CH 3 CH 3
Hg(OAc) 2 ,100°C
CH 3 CH 3 78%
CH 3 CH 3
i
9 CH 3
O H O H
O 220°C CH 3
O
O
CH 3 CON(CH 3 ) 2
TBDPSO H H H O
CH 3 H
TBDPSO 55%
CH 3
a. A. W. Burgstahler and I. C. Nordin, J. Am. Chem. Soc., 83, 198 (1961).
b. G. Saucy and R. Marbet, Helv. Chim. Acta, 50, 2091 (1967).
c. D. J. Faulkner and M. R. Petersen, J. Am. Chem. Soc., 95, 553 (1973).
d. J. W. Ralls, R. E. Lundin, and G. F. Bailey, J. Org. Chem., 28, 3521 (1963).
e. L. A. Paquette, T.-Z. Wang, S. Nang and C. M. G. Philippo, Tetrahedron Lett., 34, 3523 (1993).
f. K. Mitami, K. Takahashi, and T. Nakai, Tetrahedron Lett., 28, 5879 (1987).
g. S. D. Rychnovsky and J. L. Lee, J. Org. Chem., 60, 4318 (1995).
h. T. Berkenbusch and R. Brueckner, Chem. Eur. J., 10, 1545 (2004).
i. T.-Z. Wang, E. Pinard, and L. A. Paquette, J. Am. Chem. Soc., 118, 1309 (1996).
Entry 7 illustrates reaction conditions that were applicable to formation and
rearrangement of an isopropenyl allylic ether. The tri-isopropylaluminum is thought
to both catalyze the sigmatropic rearrangement and reduce the product ketone.