Chemistry Reference
In-Depth Information
Ti(O
i
-Pr)
4
,
EtMgBr
O
TBSO
TBSO
TBSO
TBSO
OEt
OH
5.331
5.332
1. MsCl, Et
3
N
2. MgBr
2
TBSO
TBSO
Br
5.333
Scheme 5.88
with ester
5.326
gave the cyclopropanol
5.327
, which underwent ring opening on heating with aqueous base.
Given the high
-character of the cyclopropane C-C bonds, cyclopropanols may be viewed as homo-enols,
making this conversion to the ketone analogous to enol-ketone tautomerism. Upon double deprotection, the
spiroketal
5.330
was obtained.
The ester Kulinkovich reaction was used to prepare a key allylic bromide
5.333
in a synthesis of neolauli-
malide and isolaulimalide (Scheme 5.88).
99
The cyclopropanol
5.332
produced by the Kulinkovich reaction
of ester
5.331
, as its mesylate, was subjected to ring opening with magnesium bromide. This is likely to
involve electrocyclic ring opening of the cyclopropyl carbocation, followed by bromide trapping.
References
1. (a) de Meijere, A.; Meyer, F. E.
Angew. Chem., Int. Ed. Engl.
1994
,
33
, 2379; (b) Cabri, W.; Candiani, I.
Acc. Chem.
Res.
1995, 28, 2; (c) Heck, R. F.
Organic Reactions
1982
,
27
, 345; (d) Crisp, G. T.
Chem. Soc. Rev.
1998
,
27
, 427.
2. Franck, W. C.; Kim, Y. C.; Heck, R. F.
J. Org. Chem.
1978
,
43
, 2947.
3. Jeffrey, T.
Synthesis
1987
, 70.
4. Patel, B. A.; Ziegler, C. B.
etal.J.Org.Chem.
1977
,
42
, 3903.
5. Bates, R. W.; Gabel, C. J.
Tetrahedron Lett.
1993
,
34
, 3547.
6. Tao, W.; Nesbitt. S.; Heck, R. F.
J. Org. Chem.
1990
,
55
, 63.
7. Cabri, W.; Candiani, I.
Acc. Chem. Res.
1995
,
28
,2.
8. Draper, T. L.; Bailey, T. R.
Synlett
1995
, 157.
9. (a) Taylor, J. G.; Moro, A. V.; Correia, C. R. D.
Eur. J. Org. Chem.
2011
, 1403; (b) Roglans, A.; Pla-Quintana, A.;
Moreno-Manas, M.
Chem. Rev.
2006
,
106
, 4622.
10. Werner, E. W.; Sigman, M. S.
J. Org. Chem.
2011
,
133
, 9692.
11. Baumeister, P., Meyer, W.
et al. Chimia
1997
,
51
, 144.
12. Schmidt, B.; H olter, F.
Chem. Eur. J.
2009
,
15
, 11948; see also Schmidt, B.; H olter, F.
etal.J.Org.Chem
.
2011
,
76
,
3357.
13. (a) Spencer, A.
J. Organomet. Chem.
1983
,
247
, 117; (b) Blaser, H. U.; Spencer, A.
J. Organomet. Chem.
1982
,
233
,
267.
14. (a) Andersson, C.-M.; Hallberg, A.
J. Org. Chem.
1988
,
53
, 4257; (b) Andersson, C.-M.; Hallberg, A. J.
Tetrahedron
Lett.
1987
,
28
, 4215.
15. Spencer, A.
J. Organomet. Chem.
1984
,
265
, 323
16. Herrmann, W. A.; Brossmer, C.
Angew. Chem., Int. Ed. Engl.
1995
,
34
, 1844.
17. Netherton, M. R.; Fu, G. C.
Org. Lett.
2001
,
3
, 4295.
18. Ref 5 Jeffrey, T.
Tetrahedron
1996
,
52
, 10113.
19. Plevyak, J. E.; Heck, R. F.
J. Org. Chem.
1978
,
43
, 2454.
20. Raggon, J. W.; Snyder, W. M.
Org. Process Res. Dev.
2002
,
6
, 67.
