Categories: C-C Bond Formation > Chains >
Synthesis of 1,3-dienes
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Recent Literature
An efficient new route by coupling Grignard reagents and dienol phosphates in
the presence of Fe(acac)3 allows a stereoselective preparation of
terminal conjugated dienes.
G. Cahiez, V. Habiak, O. Gager, Org. Lett., 2008,
10, 2389-2392.
A mild, stereospecific cross-coupling of unsymmetrical
1,4-bissilyl-1,3-butadienes has been developed. A selective cross-coupling
under mildly basic conditions afforded 4-aryl-1,3-dienylsilanes in excellent
yield for a wide range coupling partners. The subsequent cross-coupling of
the 4-aryl-1,3-dienylsilanes could be effected cleanly by the action of TBAF
with electron-rich or electron-poor halides.
S. E. Denmark, S. A. Tymonko, J. Am. Chem. Soc.,
2005,
127, 8004-8005.
S. E. Denmark, S. A. Tymonko, J. Am. Chem. Soc.,
2005,
127, 8004-8005.
The rhodium-catalyzed reaction of aryl boronic acids with internal alkynes
and acrylates in water gives the domino coupling products. The reaction
demonstrates that water offers the possibility to discover novel
transformations.
T. Kurahashi, H. Shinokubo, A. Osuka, Angew. Chem. Int. Ed., 2006,
45, 6336-6338.
Exposure of aldehydes or α-ketoesters to acetylene and hydrogen gas at
ambient temperature and pressure in the presence of a cationic rhodium catalysts
provides the products of a formal carbonyl Z-butadienylation. These
multicomponent couplings represent the first use of acetylene gas in
metal-catalyzed reductive C-C bond formation.
J. R. Kong, M. J. Krische, J. Am. Chem. Soc., 2006,
128, 16040-16041.
Catalytic hydrogenation of 1,3-enynes in the presence of ethyl glyoxalate at
ambient pressure and temperature using a rhodium catalyst modified by (R)-(3,5-tBu-4-MeOPh)-MeO-BIPHEP
results in highly regio- and enantioselective reductive coupling to furnish the
corresponding α-hydroxy esters.
Y.-T. Hong, C.-W. Cho, E. Skucas, M. J. Krische, Org. Lett., 2007,
9, 3745-3748.
Highly enantioselective direct catalytic reductive couplings of 1,3-enynes
to activated ketones such as ethyl pyruvate have been achieved by using
chirally modified cationic rhodium catalysts in the presence of hydrogen to
afford dienylated α-hydroxy esters with exceptional levels of regio- and
enantiocontrol.
J.-R. Kong, M.-Y. Ngai, M. J. Krische, J. Am. Chem. Soc.,
2006,
128, 718-719.
Hydroboration of a variety of 1-bromo-1-acetylenes with dicyclohexyl borane,
reaction with t-BuLi, and transmetalation to zinc generates a (Z)-disubstituted
vinylzinc reagent. In situ reaction of this reagent with aldehydes generates
(Z)-disubstituted allylic alcohols in high yields.
S.-J. Jeon, E. L. Fischer, P. J. Carroll, P. J. Walsh, J. Am. Chem. Soc.,
2006,
128, 9618-9619.
