Categories: C-B Bond Formation > Synthesis of boronic acids and boronates >
Synthesis of vinylboronic acids and vinylboronates
Related |
 |
|
Name Reactions
Recent Literature
Methylpentanediolborane can be prepared easily by reaction of hexyleneglycol
with borane dimethylsulfide or B2H6 generated from NaBH4
and I2. MPBH hydroborates stereo- and regioselectively highly
functionalized alkynes. MPBH compares favorably with pinacolborane in terms of
reactivity. The obtained vinylboronic esters are air- and chromatography-stable.
N. PraveenGanesh, S. d'Hondt, P. Y. Chavant, J. Org. Chem., 2007,
72, 4510-4514.
Preparation of (E)-1-Alkenylboronic Acid Pinacol Esters via Transfer of
Alkenyl Group from Boron to Boron
K. Shirakawa, A. Arase, M. Hoshi, Synthesis,
2004,
1814-1820.
4-Substituted 1,2-oxaborol-2(5H)-ols were prepared through
copper-catalyzed carbomagnesation of propargyl alcohol, followed by the
transmetallation of magnesium to boron in a one-pot procedure. The
Suzuki-Miyaura cross-coupling of these new 2,2-disubstituted alkenylboronic
acids with aryl halides afforded stereodefined 2,3-disubstituted allyl
alcohols in good to excellent yields.
G.-H. Fang, Z.-J. Yan, M.-Z. Deng,
Synthesis, 2006, 1148-1154.
A new method for the synthesis of organoborates starting from α,β-unsaturated
acetals was developed. The available alkoxy-functionalized butadienyl- and
styrylboronic esters cross couple effectively with a broad spectrum of aryl
halides under mild conditions. This method provides an effective
approach to aromatic ketones.
P. B. Tivola, A. Deagostino, C. Prandi, P. Venturello, Org. Lett.,
2002,
4, 1275-1277.
The Cross-coupling reaction of bis(pinacolato)diboron with
β-(trifluoromethanesulfonyloxy)-α,β-unsaturated carbonyl compounds was carried
out in the presence of PdCl2(PPh3)2-2PPh3
(3 mol%) and KOPh in toluene or K2CO3 in dioxane for the
synthesis of cyclic and acyclic β-boryl-α,β-unsaturated esters, amides, and
ketones in high yields.
J. Takagi, A. Kamon, T. Ishiyama, N. Miyaura, Synlett., 2002,
1880-1882.
Alkynylboration of alkynes with alkynyl(pinacol)boranes in the presence of
nickel catalysts gave cis-1-borylbut-1-en-3-yne derivatives. Some
boryl-substituted enynes were reacted with sp2 halides under
Suzuki-Miyaura coupling conditions.
M. Suginome, M. Shirakura, A. Yamamoto, J. Am. Chem. Soc., 2006,
128, 14438-14439.
In the presence of a chiral phosphoramidite ligand, the palladium-catalyzed
diboration of allenes can be executed with high enantioselectivity with a range
of aromatic and aliphatic allenes. A mechanism is proposed based on
isotopic-labeling experiments, stereodifferentiating reactions, kinetic analysis,
and computational experiments.
H. E. Burks, S. Liu, J. P. Morken, J. Am. Chem. Soc., 2007,
129, 8766-8773.
Pd-catalyzed diboration of prochiral allenes occurs exclusively at the
internal position and is accelerated in the presence of Lewis basic ligands.
A chiral ligand was employed, and the enantiomeric excess of a variety of
diboration products was found to be in the range of 86-92% ee.
N. F. Pelz, A. R. Woodward, H. E. Burks, J. D. Sieber, J. P. Morken, J. Am. Chem. Soc.,
2004,
126, 16328-16329.
Related:
The cobalt-catalyzed Diels-Alder reaction of alkynyl pinacol boronic esters with various dienes generates cycloadducts in very good regioselectivity. A reaction sequence (Diels-Alder reaction, Suzuki coupling, DDQ oxidation) was successfully performed as a one pot operation without isolation of the intermediates.
G. Hilt, K. I. Smolko, Angew. Chem. Int. Ed., 2003, 42,
2795-2797.
1-Alkenylboronic acid pinacol esters have been synthesized via a palladium-catalyzed cross-coupling reaction of bis(pinacolato)diboron with 1-alkenyl halides or triflates in toluene at 50°C in the presence of KOPh in high yields with complete retention of configuration of the double bonds. A one-pot synthesis of unsymmetrical 1,3-dienes via the borylation-coupling sequence has been developed.
J. Takagi, K. Takahashi, T. Ishiyama, N. Miyaura, J. Am. Chem. Soc.,
2002,
124, 8001-8006.
Pd-catalyzed enantioselective diborations of prochiral allenes followed by allylation reactions with primary imines provide vinyl boronates which may be oxidized to give nonracemic Mannich products. Alternatively, enantiomerically enriched homoallylic amine derivatives may be obtained by protonation and Suzuki cross-coupling of the vinyl boronate.
J. D. Sieber, J. P. Morken, J. Am. Chem. Soc.,
2006,
128, 74-75.
