Categories: C-B Bond Formation > Synthesis of boronic acids and boronates >
Synthesis of allylboronic acids and allylboronates
Related |
|
Recent Literature
Aliphatic, aromatic, heteroaromatic, vinyl, or allylic Grignard reagents react
with pinacolborane at ambient temperature in tetrahydrofuran to afford the
corresponding pinacolboronates. The initially formed dialkoxy alkylborohydride
intermediate quickly eliminates hydridomagnesium bromide and affords the product
boronic ester in very good yield. This reaction also can be carried out under
Barbier conditions.
J. W. Clary, T. J. Rettenmaier, R. Snelling, W. Bryks, J. Banwell, W. T. Wipke,
B. Singaram, J. Org. Chem., 2011,
76, 9602-9610.
A palladium pincer complex catalyzes an allylic C-H borylation of alkenes in
high yields. The transformation exhibits high regio- and stereoselectivity with
various linear alkenes. Preliminary mechanistic studies indicate that this C-H
borylation reaction proceeds via Pd(IV) pincer complex intermediates.
L. Mao, R. Bertermann, K. Emmert, K. J. Szabo, T. B. Marder, Org. Lett.,
2017, 19, 6586-6589.
An iron-catalyzed direct SN2' dehydroxyboration of allylic
alcohols provides (E)-stereoselective allylboronates via a six-membered
ring transition state. Allylic alcohols with diverse structures and functional
groups, especially derived from natural products, underwent smooth
transformation.
W. Su, T.-T. Wang, X.-T. J.-R. Han, X.-L. Zhen, S.-M. Fan, Y.-X. You, Y.-K.
Zhang, R.-X. Qiao, Q. Cheng, S. Liu, Org. Lett., 2021, 23,
9094-9099.
Readily available allylic acetates are converted to allylic boronates catalyzed
by Ni/PCy3 or Ni/PPh3 complexes with high levels of
stereoselectivity and in good yields, whereas the borylation of allylic halides
can be accomplished with commercially available Pd catalysts [e.g., Pd2(dba)3,
PdCl2, Pd/C].
P. Zhang, I. A. Roundtree, J. P. Morken, Org. Lett., 2012,
14, 1363-1365.
P. Zhang, I. A. Roundtree, J. P. Morken, Org. Lett., 2012,
14, 1363-1365
The use of low-cost iron(III) acetoacetate and tetramethylethylenediamine (TMEDA)
enables a mild direct cross-coupling of alkyl halides with
bis(pinacolato)diboron at room temperature. Moreover, the borylation of benzylic
or allylic chlorides, tosylates, and mesylates is possible. The reactions show
broad functional-group compatibility.
T. C. Atack, R. M. Lecker, S. P. Cook, J. Am. Chem. Soc., 2014,
136, 9521-9523.
A copper-catalyzed γ-selective and stereospecific substitution reaction of
allylic carbonates with bis(pinacolato)diboron afforded allylboron
compounds. Functionalized allylboronates that have an acetal, ester, or
isolated alkene were prepared. The reaction of optically active allylic
carbonates underwent complete chirality transfer.
H. Ito, C. Kawakami, M. Sawamura, J. Am. Chem. Soc.,
2005,
127, 16034-16035.
Cu(I)-catalyzed enantioselective substitution of readily available allylic
carbonates with bis(pinacolato)diboron afforded various α-chiral allylboronates,
including functionalized allylboronates, with high enantiomeric purity.
H. Ito, S. Ito, Y. Sasaki, K. Matsuura, M. Sawamura, J. Am. Chem. Soc., 2007,
129, 14856-14857.
A remarkably simple and effective system allows a direct conversion of allylic
alcohols into high value allylic boronic esters using commercially available
reagents and catalysts.
G. Dutheuil, N. Selander, K. J. Szabó, V. K. Aggarwal, Synthesis, 2008,
2293-2297.
A copper-catalyzed synthesis of benzyl-, allyl-, and allenyl-boronates from
benzylic, allylic, and propargylic alcohols, respectively, exhibits a broad
reaction scope and high efficiency under mild conditions. Preliminarily
mechanistic studies suggest that nucleophilic substitution is involved in this
reaction.
L. Mao, K. J. Szabó, T. B. Marder, Org. Lett.,
2017, 19, 1204-1207.
A copper(I)-catalyzed regio- and stereoselective three-component coupling
reactions between gem-dialkylallenes, alkyl halides, and bis(pinacolato)diboron provides sterically congested allylic
boronates. A subsequent allylboration of
aldehydes diastereoselectively furnished the corresponding homoallylic alcohols
that bear a quaternary carbon.
Y. Ozawa, K. Endo, H. Ito, J. Am. Chem. Soc.,
2021, 143, 13865-138772.
Phosphine-free Pd complexes together with alkenyl or aryl iodides were very
efficient catalysts for 1,2-diboration of allenes. This reaction is completely
regioselective and highly stereoselective. Monosubstituted allenes afford
diboration products with mainly Z stereochemistry.
F.-Y. Yang, C.-H. Cheng, J. Am. Chem. Soc., 2001,
123, 761-762.
A copper(I)-catalyzed γ-boryl substitution of allyl acylals enables an
enantioselective synthesis of α-chiral γ-acetoxyallylboronates with high E/Z
selectivity and enantioselectivity. A subsequent reaction with aldehydes
provides monoprotected anti-1,2-diol derivatives with high
stereoselectivity.
Y. Takenouchi, R. Kojima, R. Momma, H. Ito,
Synlett, 2017, 28, 270-274.
A new method for the synthesis of substituted 2-acylallylmetal reagents in a
highly regio- and stereoselective fashion involving a three-component
assembly of allenes, acyl chlorides, and bimetallic reagents (B-B, Si-Si,
and Sn-Sn) catalyzed by phosphine-free palladium complexes is described.
F.-Y. Yang, M. Shanmugasundaram, S.-Y. Chuang, P.-J. Ku, M.-Y. Wu, C.-H.
Cheng, J. Am. Chem. Soc.,
2003,
125, 12576-12583.
Palladium-catalyzed coupling reactions of functionalized allylboronic acids
with various iodobenzenes under standard Suzuki-Miyaura coupling conditions
afforded selectively the branched allylic products in high to excellent
yields.
S. Sebelius, V. J. Olsson, O. A. Wallner, K J. Szabó, J. Am. Chem. Soc.,
2006,
128, 8150-8151.
S. Sebelius, V. J. Olsson, O. A. Wallner, K J. Szabó, J. Am. Chem. Soc.,
2006,
128, 8150-8151.
A copper-catalyzed formal SN2' defluorinative borylation of
3-substituted 3,3-difluoropropenes provides 3-fluoroallylboronic esters in high
yields with excellent Z:E ratios. The primary 3-fluoroallylboronic esters
undergo several synthetic sequences involving sigmatropic rearrangements, SE2'
substitutions, and SN2' substitutions to give tertiary allylic
fluorides.
T. W. Butcher, J. L. Yang, J. F. Hartwig,
Org. Lett., 2020, 22, 6805-6809.
A ruthenium-catalyzed hydroboration of ynones provides vinyl
α-hydroxylboronates under mild conditions. This reaction features high
efficiency, a broad scope, and complete chemo-, regio-, and stereoselectivity,
in spite of many possible competitive pathways.
Q. Feng, S. Li, Z. Li, Q. Yan, X. Lin, L. Song, X. Zhang, Y.-D. Wu, J. Sun, J. Am. Chem. Soc.,
2022, 144, 14846-14855.
In situ generation of allylic boronates by iridium-catalyzed borylation of
cyclic alkenes in the presence of additives, such as methylimidazole and DBU,
followed a reaction with aldehydes allows the synthesis of stereodefined
homoallylic alcohols. Cycloalkenes without additives as well as acyclic
substrates gave vinylic boronates, which were coupled with organohalides in a
Suzuki-Miyaura sequence.
V. J. Olsson, K. J. Szabó, J. Org. Chem., 2009,
74, 7715-7723.
A chemo-, regio-, and stereoselective iron-catalyzed 1,4-hydroboration of dienes
affords γ-disubstituted allylboronates. 1,4-Hydroboration of 2-substituted
dienes forms products with (E)-trisubstituted double bonds exclusively.
J. Y. Wu, B. Moreau, T. Ritter, J. Am. Chem. Soc., 2009,
131, 12915-12917.
Cu-catalyzed highly regio- and stereoselective 1,4-protoboration of
dienylboronates provides unsymmetrical 1,4-bifunctional allylboron reagents. A
subsequent chemoselective allylboration with aldehydes followed by oxidative
workup give diol products with high diastereoselectivity.
S. Gao, M. Wang, M. Chen, Org. Lett.,
2018, 20, 7921-7925.
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.
An efficient Cu-catalazed borylation of propargylic alcohols provides vinyl-,
allyl-, and (E)-2-boryl allylboronates in very good yield with a broad
substrate scope under mild conditions. Isolation of an allenyl boronate as the
reaction intermediate suggests that an insertion-elimination-type reaction,
followed by borylcupration, is involved.
L. Mao, R. Bertermann, K. Emmert, K. J. Szabo, T. B. Marder, Org. Lett.,
2017, 19, 6586-6589.
Related:
Catalyzed by a chiral palladium complex, 1,1-bis(pinacolboronate) esters undergo
asymmetric cross-coupling with bromoalkenes to generate allyl boronates with
high levels of enantioselectivity. Oxidation of these allyl boronates with
hydrogen peroxide provides secondary allylic alcohols, whereas nitrosobenzene as
oxidant furnishes nonracemic tertiary allylic alcohols.
B. Potter, A. A. Szymaniak, E. K. Edelstein, J. P. Morken, J. Am. Chem. Soc., 2014,
136, 17918-17921.
Bifunctional vinylboroate/allylic acetate esters react with Grignard reagents to
form tertiary allylic boronates via an 'ate-mediated allylic substitution' (AMAS)
approach. The method tolerates a wide range of substrates and Grignard reagents.
B. A. Ondrusek, J. K. Park, D. T. McQuade, Synlett, 2014, 25,
217-220.
Bis[(pinacolato)boryl]methylzinc halides are solid storable reagents that can be
used in
copper-catalyzed coupling reactions with vinyliodonium salts under mild conditions. The
reaction shows broad scope with respect to vinyliodonium salts, affording
various α-boryl-substituted allylboronate esters in good yields. Synthetic
applications of the obtained products are also demonstrated.
M. Shin, M. Kim, C. Hwang, H. Lee, H. Kwon, J. Park, E. Lee, S. H. Cho,
Org. Lett., 2020, 22, 2476-2480.
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.