Categories: C-C Bond Formation > Oxygen-containing molecules > α,β-unsaturated compounds >
Synthesis of Baylis-Hillman adducts
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Recent Literature
An efficient method for the synthesis of multifunctionalized alkenes has
been developed. In the presence of 5 mol% CuI as catalyst, an organozinc
species CF3COOZnR reacted with α,β-acetylenic ketones and
aldehydes in one pot providing trisubstituted alkenes in high yields with
high stereoselectivity. The reaction with β-substituted-α,β-acetylenic
ketones gave tetrasubstituted alkenes in good yields with Z-isomers as the
major products.
S. Xue, L. He, Y.-K. Liu, K.-Z. Han, Q.-X. Guo,
Synthesis, 2006, 666-674.
Highly substituted α,β-unsaturated ketones are prepared by the N-heterocyclic
carbene-initiated addition of α-hydroxypropargylsilanes to aldehydes. This
strategy serves as a highly efficient alternative to the Morita-Baylis-Hillman
reaction.
T. E. Reynolds, C. A. Stern, K. A. Scheidt, Org. Lett., 2007,
9, 2581-2584.
Silyloxyallenes derived from α-hydroxypropargylsilanes add efficiently to
aldehydes with catalytic amounts of Lewis acids. The allenes are accessed
from the corresponding propargylsilanes in a base-catalyzed 1,2-Brook
rearrangement/SE2' process. Conversion to the silyloxyallenes
occurs with minimal erosion in optical activity.
T. E. Reynolds, A. R. Bharadwaj, K. A. Scheidt, J. Am. Chem. Soc., 2006,
128, 15382-15383.
A stereoselective multicomponent synthesis of (Z)-β-bromo
Baylis-Hillman ketones uses MgBr2 as both the Lewis acidic promoter
and the bromine source for the Michael-type addition with α,β-acetylenic ketones
to form an active β-bromo allenolate intermediate, which in turn attacks various
aldehydes to afford β-bromo Baylis-Hillman adducts in good yields and Z-selectivity.
H.-X. Wei, R. L. Jasoni, J. Hu, G. Li, P. W. Pare, Tetrahedron,
2004, 60, 10233-10237.
A simple and highly stereoselective method has been developed for the
synthesis of (Z)-β-iodo Baylis-Hillman adducts using CeCl3·7H2O/NaI
as an inexpensive and readily available reagent system.
J. S. Yadav, B. V. S. Reddy, M. K. Gupta, B. Eeshwaraiah, Synthesis,
2005, 57-60.
Using a catalytic amount of trialkylphosphines, alkyl halides undergo
efficient intramolecular Morita-Baylis-Hillman cyclization.
M. E. Krafft, K. A. Seibert, Synlett, 2006,
3334-3336.
An organomediated, intramolecular Morita-Baylis-Hillman reaction of
molecules bearing allylic leaving groups as the electrophilic partner
provided a facile, high yielding, straightforward synthesis of densely
functionalized cyclic molecules.
M. E. Krafft, T. F. N. Haxell, J. Am. Chem. Soc.,
2005,
127, 10168-10169.
An efficient cycloallylation of mono-enone mono-allylic carbonates is
achieved upon exposure to tributylphosphine and 1 mol % Pd(Ph3P)4.
This transformation combines the nucleophilic features of the
Morita-Baylis-Hillman reaction with the electrophilic features of the
Trost-Tsuji reaction.
B. G. Jellerich, J.-R. Kong, M. J. Krische, J. Am. Chem. Soc.,
2003,
125, 7758-7759.
