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Reduction of carbonyl compounds
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Corey-Bakshi-Shibata Reduction
Meerwein-Ponndorf-Verley Reduction (MPV)
Recent Literature
[Cp*Ir(2,2′-bpyO)(H2O)] is a highly efficient and general catalyst
for transfer hydrogenation of carbonyl compounds and chemoselective transfer
hydrogenation of unsaturated aldehydes with isopropanol under neutral conditions.
The reaction tolerates deducible groups such as nitro, cyano, ester, and halide.
R. Wang, Y. Tang, M. Xu, C. Meng, F. Li, J. Org. Chem., 2018, 83,
2274-2281.
Low loadings of AgSbF6 catalyze the hydroboration of nitriles,
alkens, and aldehydes under base- and solvent-free conditions. This
atom-economic chemoselective protocol shows excellent functional group tolerance
and compatibility with structurally and electronically diverse substrates.
V. K. Pandey, C. S. Tiwari, A. Rit, Org. Lett., 2021, 23,
1681-1686.
A boron-functionalized heptaphosphide Zintl cluster catalyzes a transition
metal-free hydroboration of aldehydes and ketones. Moreover, the greenhouse gas
carbon dioxide was efficiently and selectively reduced to methoxyborane.
B. van IJzendoorn, S. F. Albawardi, I. J. Votorica-Yrezabal, G. F. S.
Whitehead, J. E. McGrady, M. Mehta, J. Am. Chem. Soc.,
2022, 144, 21213-21223.
A catalytic amount of titanium tetrachloride immensely accelerates the
hydroboration-hydrolysis (reduction) of ketones with ammonia borane in diethyl
ether at room temperature. The product alcohols are produced in very good yields
within 30 min, even with ketones which typically requires 24 h or longer under
uncatalyzed conditions.
P. V. Ramachandran, A. A. Alawaed, H. J. Hamann, J. Org. Chem., 2022, 87,
13259-13269.
An anionic iridium complex [Cp*Ir(2,2'-bpyO)(OH)][Na] is a general and highly
efficient catalyst for transfer hydrogenation of ketones and imines with
methanol as hydrogen source under base-free conditions. Nitro, cyano, and ester
groups were tolerated under the reaction conditions.
R. Wang, X. Han, J. Xu, P. Liu, F. Li, J. Org. Chem., 2020, 85,
2242-2249.
Sodium aminodiboranate (NaNH2(BH3)2, NaADBH) is
a member of the borane family with superior performance in chemoselective
reduction. NaADBH can rapidly reduce aldehydes and ketones to the corresponding
alcohols in high efficiency and selectivity under mild conditions. Steric and
electronic effects have only a limited influence.
J. Wang, Y. Guo, S. Li, X. Chen, Synlett, 2021, 32,
1104-1108.
A combination of a chiral Ru complex and KOtBu catalyzes an asymmetric
transfer hydrogenation of various benzaldehyde-1-d derivatives with 2-propanol
to yield (R)-benzyl-1-d alcohols in high ee and with high isotopic purity.
Reaction of benzaldehydes with a DCO2D-triethylamine mixture and the
same Ru catalyst affords the S deuterated alcohols in high ee.
I. Yamada, R. Noyori,
Org. Lett., 2000, 2, 3425-3427.
A copper-catalyzed (Cu(OAc)2ˇH2O/(R)-3,4,5-MeO-MeO-BIPHEP)
reduction of aryl/heteroaryl ketones provides nonracemic secondary alcohols in
very good yields with excellent ee values in an aqueous micellar medium in the
presence of PMHS as inexpensive, innocuous, and convenient stoichiometric
hydride source.
D. M. Fialho, E. Etemadi-Davan, O. C. Langner, B. S. Takale, A. Gadakh, G.
Sambasivam, B. H. Lipshutz, Org. Lett., 2021, 23,
3283-3286.
PhanePhos-ruthenium-diamine complexes efficiently catalyze an asymmetric
hydrogenation of a wide range of aromatic, heteroaromatic, and α,β-unsaturated
ketones with excellent enantioselectivity.
M. J. Burk, W. Hems, D. Herzberg, C. Malan, A. Zanotti-Gerosa,
Org. Lett., 2000, 2, 4173-4176.
An air stable iridium complex of ferrocene-based phosphine-oxazoline ligand exhibits excellent performance for the asymmetric hydrogenation of simple
ketones. Exo-α,β-unsaturated
cyclic ketones could also be regiospecifically hydrogenated to give chiral allylic
alcohols with good results.
Y. Wang, G. Yang, F. Xie, W. Zhang, Org. Lett.,
2018, 20, 6135-6139.
An electrochemical reduction of carbonyl compounds, including ketones and
aldehydes provides a variety of alcohols or diols as major products with decent
yields. This sustainable and practical reaction proceeds smoothly in air at
ambient temperatures with DABCO as the sacrificial reductant. The direct
electrochemical reduction is either followed by protonation or radical-radical
homocoupling.
L. Wang, X. Zhang, R. Y. Xia, C. Yang, L. Guo, W. Xia, Synlett, 2022,
33,
1302-1308.
Aryl ketones were reduced to the corresponding alcohols with excellent
enantioselectivity by trichlorosilane in the presence of a catalytic amount of
N-formyl-α'-(2,4,6-triethylphenyl)-L-proline as an activator.
Y. Matsumura, K. Ogura, Y. Kouchi, F. Iwasaki, O. Onomura, Org. Lett.,
2006, 8, 3789-3792.
The catalytic asymmetric borane reduction of both electron-deficient and
electron-rich ketones was achieved with high enantioselectivity with a C3-symmetric
chiral tris(β-hydroxy phosphoramide) ligand .
D.-M. Du, T. Fang, J. Xu, S.-W. Zhang, Org. Lett.,
2006, 8, 1327-1330.
A family of chiral iminophenyl oxazolinylphenylamines (IPOPA) ligands enables an
efficient cobalt-catalyzed asymmetric hydrosilylation of simple ketones with a
low catalyst loading of CoCl2 to afford chiral alcohols in good
yields with high enantioselectivities.
X. Chen, Z. Lu, Org. Lett.,
2016, 18, 4658-4661.
Various N-(p-Tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine
ligands have been prepared, characterized, and evaluated in the Rh-catalyzed asymmetric
transfer hydrogenation (ATH) of a wide range of (hetero)aryl ketones under mild
conditions with the formic acid/triethylamine (5:2) system as the hydrogen
source. Ligands bearing electron-donating groups exhibited a higher catalytic
activity than those having electron-withdrawing groups.
L.-S. Zheng, Q. Llopis, P.-G. Echeverria, C. Férard, G. Guillamot, P. Phansavath
V. Ratovelomanana-Vidal, J. Org. Chem.,
2017, 82, 5607-5615.
A complex of CuH and Takasago's nonracemic ligand, DTBM-SEGPHOS, is an
especially reactive reagent for asymmetric hydrosilylation of heteroaromatic
ketones under very mild conditions. PMHS serves as an inexpensive source of
hydride for the in situ generation of CuH.
B. H. Lipshutz, A. Lower, K. Noson, Org. Lett.,
2002, 4, 4045-4048.
The combination of lipase and a ruthenium complex catalyzes the asymmetric
transformation of enol acetates or ketones to chiral acetates in high yields
with high optical purities in the presence of 2,6-dimethylheptan-4-ol as a
hydrogen donor and 4-chlorophenyl acetate as an acyl donor.
H. M. Jung, J. H. Koh, M.-J. Kim, J. Park,
Org. Lett., 2000, 2, 397-399.
Ketones were transformed to chiral acetates by a one-pot process using a lipase
and an achiral ruthenium complex under 1 atm of hydrogen gas in ethyl acetate.
The same catalyst system was also effective for an asymmetric transformation of
enol acetates to acetates under hydrogen without additional acyl donors.
H. M. Jung, J. H. Koh, M.-J. Kim, J. Park,
Org. Lett., 2000, 2, 2487-2490.
An efficient reduction of various prochiral ketones such as acetopehones,
α-azido aryl ketones, β-ketoesters, and aliphatic acyclic and cyclic ketones to
the corresponding optically active secondary alcohols with good chemical yield
was achieved by using Daucus carota, root plant cells under extremely
mild and environmentally benign conditions in aqueous medium.
J. S. Yadav, S. Nanda, P. T. Reddy, A. Bhaskar, Rao, J. Org. Chem., 2002,
67, 3900-3903.
A chiral oxazaborolidinium ion (COBI) catalyst enables a highly enantioselective
hydrosilylation of ketones for the synthesis of various chiral secondary
alcohols in good yields and excellent enantioselectivities.
B. C. Kang, S. H. Shin, J. Yun, D. H. Ryu, Org. Lett.,
2017, 19, 6316-6319.
A chemoselective reduction of the carbonyl functionality via hydrosilylation
using low loadings of a copper(I) catalyst bearing an abnormal NHC takes place
at ambient temperature in excellent yield within a very short reaction time. The
hydrosilylation reaction of α,β-unsaturated carbonyl compounds gives allyl
alcohols in good yields. The catalyst can also be used for azide-alkyne
cycloadditions.
S. R. Roy, S. C. Sau, S. K. Mandal, J. Org. Chem.,
2014,
79, 9150-9160.
Small amounts of n-BuLi catalyze a highly efficient and selective
hydroboration of aldehydes and ketones with HBpin. The reaction proceeds rapidly
under mild conditions with exceptional functional group compatibility, ample
substrate scope, and high selectivity for aldehydes over ketones.
Z. Zhu, X. Wu, X. Xu, Z. Wu, M. Xue, Y. Yao, Q. Shen, X. Bao, J. Org. Chem., 2018, 83,
10677-10683.
A nonanuclear copper(II) complex obtained by a facile one-pot self-assembly
catalyzes the hydroboration of ketones and aldehydes with the absence of an
activator under mild, solvent-free conditions. The air- and moisture-stable
catalyst displays high efficiency and chemoselectivity on aldehydes over ketones
and ketones over imines.
H. Zeng, J. Wu, S. Li, C. Hui, A. Ta, S.-Y. Cheng, S. Zheng, G. Zhang, Org. Lett.,
2019, 21, 401-406.
A recyclable cobalt(II)-terpyridine coordination polymer (CP) is a highly
effective hydroboration precatalyst for reductions of ketones, aldehydes, and
imines with pinacolborane (HBpin). A wide range of substrates containing polar
C=O or C=N bonds have been hydroborated selectively in excellent yields under
ambient conditions.
J. Wu, H. Zeng, J. Cheng, S. Zheng, J. A. Golen, D. R. Manke, G. Zhang, J. Org. Chem., 2018, 83,
9442-9448.
Homoleptic cyclopentadienyl lanthanide complexes are excellent catalysts for
the hydroboration of various aldehydes and ketones with pinacolborane. These
robust lanthanide catalysts exhibited high reactivity with low catalyst loadings
under mild conditions, good functional group tolerability, and unique
carbonyl-selectivity.
S. Chen, D. Yan, M. Xue, Y. Hong, Y. Yao, Q. Shen, Org. Lett.,
2017, 19, 3382-3385.
The reduction of ketones with pinacolborane is catalyzed by NaOt-Bu at
ambient temperature. The reaction is high yielding and general, providing
complete conversion of aryl and dialkyl ketones. The active hydride source is
the trialkoxyborohydride, which is believed to be present in low concentration
under the reaction conditions.
I. P. Query, P. A. Squier, E. M. Larson, N. A. Isley, T. B. Clark, J. Org. Chem., 2011,
76, 6452-6456.
An operationally convenient hydroboration of aldehydes and ketones employing
Fe(acac)3 as precatalyst proceeded efficiently at room temperature to
yield, after work up, 1° and 2° alcohols. A σ-bond metathesis mechanism with an
Fe-H intermediate as key reactive species is postulated.
S. R. Tamang, M. Findlater, J. Org. Chem.,
2017, 82, 12857-12862.
NHC-boranes such as 1,3-dimethylimidazol-2-ylidine trihydridoborane serve as
practical hydride donors for the reduction of aldehydes and ketones in the
presence of silica gel to give alcohols in good yields under ambient conditions.
Aldehydes are selectively reduced in the presence of ketones. The process is
attractive because all the components are stable and easy to handle and because
the isolation procedure is convenient.
T. Taniguchi, D. P. Curran, Org. Lett., 2012,
14, 4540-4543.
Activation of diphenylsilane in the presence of a catalytic amount of an
N-heterocyclic carbene (NHC) enables hydrosilylation of carbonyl derivatives
under mild conditions. Presumably, a hypervalent silicon intermediate featuring
strong Lewis acid character allows dual activation of both the carbonyl moiety
and the hydride at the silicon center. Some interesting selectivities have been
encountered.
Q. Zhao, D. P. Curran, M. Malacria, L. Fensterbank, J.-P. Goddard, E. Lacôte, Synlett, 2012, 23,
433-437.
Decaborane was found to be an effective agent for the chemoselective
reduction of ketones to alcohols in the presence of pyrrolidine and cerium(III)
chloride heptahydrate in methanol.
J. W. Bae, S. H. Lee, Y. J. Jung, C.-O. Maing, C. M. Yoon, Tetrahedron Lett., 2001, 42, 2137-2139.
A highly efficient silver-catalyzed chemoselective method enables the reduction
of aldehydes to their corresponding alcohols in water by using hydrosilanes as
reducing agents. Ketones remained essentially inert under the same reaction
conditions.
Z. Jia, M. Liu, X. Li, A. S. C. Chan, C.-J. Li, Synlett, 2013, 24,
2049-2056.
An on-water Ir(III)-diamine catalysis represents an efficient, simple and
environmentally friendly catalytic system for the transfer hydrogenation of
aldehydes. The catalyst tolerates various synthetically useful groups
including nitro groups, halogens, ketones, esters and olefins.
X. Wu, J. Liu, X. Li, A. Zanotti-Gerosa, F. Hancock, D. Vinci, J. Ruan, J.
Xiao, Angew. Chem. Int. Ed., 2006, 45, 6717-6722.
An iron complex containing electronically coupled acidic and hydridic hydrogens
catalyzes the hydrogenation of ketones under mild conditions and shows high
chemoselectivity for aldehydes, ketones, and imines. Isolated carbon double and
triple bonds, aryl halides, nitrates, epoxides, and ester functions are
unaffected by the hydrogenation conditions.
C. P. Casey, H. Guan, J. Am. Chem. Soc., 2007,
129, 5816-5817.
Sm in aqueous HCl is an environmentally benign reducing agent. Whereas
aromatic carbonyls underwent pinacol coupling reactions in an efficient manner
in Sm/2 M HCl/THF, unimolecular reductions of aliphatic aldehydes provided
alcohols.
S. Talukdar, J.-M. Fang, J. Org. Chem., 2001,
66, 330-333.
A chiral imidazole iminopyridine as a ligand enables a highly
enantioselective cobalt-catalyzed hydroboration of diaryl ketones with
pinacolborane to provide chiral benzhydrols in very good yields and ee. This
protocol could be carried out in a gram scale under mild reaction conditions
with good functional group tolerance.
W. Liu, J. Guo, S. Xing, Z. Lu,
Org. Lett., 2020, 22, 2532-2536.
An asymmetric transfer hydrogenation of diaryl ketones is promoted by
bifunctional Ru complexes with an etherial linkage between
1,2-diphenylethylenediamine (DPEN) and η6-arene ligands. An effective
discrimination of substituents on the aryl group enables a smooth reduction in a
5:2 mixture of formic acid and triethylamine with a high level of
enantioselectivity.
T. Touge, H. Nara, M. Fujiwhara, Y. Kayaki, T. Ikariya, J. Am. Chem. Soc., 2016,
138, 10084-10087.
The use of (R)-(−)-(DTBM-SEGPHOS)CuH effects a highly enantioselective
1,2-hydrosilylation of prochiral diaryl ketones to yield nonracemic
diarylmethanols in excellent yields.
C.-T. Lee, B. H. Lipshutz, Org. Lett.,
2008,
10, 4187-4190.
For highly stereoselective reductions of a large number of five- and
six-membered cyclic ketones to the most thermodynamically stable alcohols,
ketones are treated with lithium dispersion and either FeCl2ˇ4H2O
or CuCl2ˇ2H2O in THF at room temperature. This protocol is
more convenient and efficient than those commonly reported for similar
reductions.
N. Kennedy, T. Cohen, J. Org. Chem.,
2015,
80, 8134-8141.
Asymmetric transfer hydrogenation of various simple aromatic
ketones by the Ru-TsDPEN catalyst was shown to be feasible in aqueous HCOONa
without calling for any catalyst modification, furnishing ee's of up to 95% and
significantly faster rates than in the HCOOH-NEt3 azeotrope.
X. Wu, X. Li, W. Hems, F. King, J. Xiao, Org. Biomol. Chem., 2004, 2, 1818-1821.
In a biphasic reaction media for the asymmetric biocatalytic reduction of
ketones with in situ cofactor regeneration, both enzymes (ADH
and FDH) remain stable. Reductions with poorly
water-soluble ketones were carried out at substrate concentrations of > 10 mM,
and alcohols were formed with good conversions in high enantioselectivity.
H. Groeger, W. Hummel, S. Buchholz, K. Drauz, T. V. Nguyen, C. Rollmann, H.
Huesken, K. Abokitse, Org. Lett., 2003, 5, 173-176.
Pincer-aryl ruthenium(II) complexes form active catalysts in the reduction of
ketones by hydrogen transfer in i PrOH using KOH as promoter. At a KOH/Ru
molar ratio of 20/1 only trace amounts of aldol products are formed. Under these
conditions, the σ Ru-C bond is stable and the [Ru(PCP)PPh3] fragment
is preserved.
P. Dani, T. Karlen, R. A. Gossage, S. Gladiali, G. van Koten, Angew.
Chem., 2000, 112, 759-761.
The reduction of ketones and
aldehydes with lanthanide metals (La, Ce, Sm, Yb) and a catalytic amount of
iodine (5 mol %) in iPrOH proceeded smoothly to produce the
corresponding alcohols as the major products in good yield, while in THF,
methanol, and ethanol the pinacols were mainly produced. The yields of
alcohols were improved most effectively by the use of Sm metal.
S.-I. Fukuzawa, N. Nakano, T. Saitoh, Eur. J.
Org. Chem., 2004, 2863-2867.
The organic reductant 1-acetyl-2,3-dimethylimidazolidine is able to directly
reduce a series of aromatic, aliphatic and α,β-unsaturated aldehydes as well as
imines in high yields.
D. Li, Y. Zhang, G. Zhou, W. Guo, Synlett, 2008,
225-228.
In the presence of sodium formate and ethanol as hydrogen sources, a series of
alkynyl ketones were hydrogenated by a chiral spiro iridium catalyst to provide
propargylic alcohols with high enantiomeric excess.
Y.-M. Zhang, M.-L. Yuan, W.-P. Liu, J.-H. Xie, Q.-L. Zhou, Org. Lett.,
2018, 20, 4486-4489.
I. Ibrahem, A. Córdova, Angew. Chem. Int. Ed., 2006, 45, 1952-1956.
The use of diethylaluminum benzenethiolate enables an efficient discrimination
between aldehydes and other carbonyl functions and allows a chemoselective in
situ reduction of ketones and methyl esters in the presence of aldehydes without
using traditional protecting group methodologies.
G. Bastug, S. Dierick, F. Lebreux, I. E. Markó, Org. Lett., 2012,
14, 1306-1309.
A chiral atropisomeric dipyridylphosphine ligand (P-phos) forms well-defined
ruthenium complexes that offer high enantioselectivities in the catalytic
hydrogenation of 2-(6'-methoxy-2'-naphthyl)propenoic
acid and β-ketoesters.
C.-C. Pai, C.-W. Lin, C.-C. Lin, C.-C. Chen, A. S. C. Chan, W. T. Wong, J. Am. Chem. Soc., 2000,
122, 11513-11514.
The use of inexpensive rongalite as a reducing agent enables a transition
metal- and hydride-free chemoselective reduction of α-keto esters and α-keto
amides via a radical mechanism to provide a wide range of α-hydroxy esters and
α-hydroxy amides in very good yields. This mild and chemoselective method is
compatible with other reducible functionalities such as halides, alkenes,
amides, and nitriles.
S. Golla, H. P. Kokatla, J. Org. Chem., 2022, 87,
9915-9925.
The use of inexpensive rongalite as a reducing agent enables a transition
metal- and hydride-free chemoselective reduction of α-keto esters and α-keto
amides via a radical mechanism to provide a wide range of α-hydroxy esters and
α-hydroxy amides in very good yields. This mild and chemoselective method is
compatible with other reducible functionalities such as halides, alkenes,
amides, and nitriles.
S. Golla, H. P. Kokatla, J. Org. Chem., 2022, 87,
9915-9925.
Optically pure C2-symmetrical cyclic amines were
efficiently synthesized from the corresponding diols obtained from an
enantioselective borohydride reduction of diketones in the presence of a chiral
β-ketoiminato cobalt(II) catalyst.
M. Sato, Y. Gunji, T. Ikeno, T. Yamada, Synthesis, 2004,
1434-1438.
A mechanochemical asymmetric transfer hydrogenation (ATH) of diketones in the
presence of a ruthenium complex under solvent-free conditions provides chiral
1,3-diol derivatives. This protocol benefits from rapid reaction kinetics, no
use of solvents, and excellent enantioselectivity. In addition, this reaction
can easily be performed on a gram scale.
C. Wang, S. Deng, R. Chen, G. Liu, T. Cheng, R. Liu, Synlett, 2022,
33,
1858-1862.
Reduction of β-hydroxyketones by SmI2/H2O/Et3N
provided 1,3-diols in quantitative yields with no byproduct formation.
T. A. Davis, P. R. Chopade, G. Hilmersson, R. A. Flowers, Org. Lett., 2005, 7, 119-122.
A pH-independent asymmetric transfer hydrogenation of β-keto esters in water
with formic acid/sodium formate can be conducted open to air and gives access to
β-hydroxy esters in excellent yields and selectivities.
M. A. Ariger, E. M. Carreira, Org. Lett., 2012,
14, 4522-4524.
A mild, enantioselective hydrosilylation of 3-oxo-3-arylpropionic acid
methyl or ethyl esters using axially chiral BINAM N-heterocyclic carbene (NHC)-Rh(III) complexes
as catalysts gave 3-hydroxy-3-arylpropionic acid
methyl or ethyl esters in good yields with good to excellent
enantioselectivities under mild conditions.
Q. Xu, X. Gu, S. Liu, Q. Duo, M. Shi, J. Org. Chem., 2007,
72, 2240-2242.
A combination of tricyclohexylphosphine and chiral alkenylborane derived in situ
from a diyne as a frustrated Lewis pair catalyst enables a highly
enantioselective hydrosilylation of 1,2-dicarbonyl compounds. Various optically
active α-hydroxy ketones and esters were obtained in good yields with high ee’s.
X. Ren, H. Du, J. Am. Chem. Soc., 2016,
138, 810-813.
Red-Al is an efficient chelation-controlled reducing reagent for acyclic
acetal-protected R-hydroxy ketones. Typically, high diastereomeric ratios
and yields can be achieved for the synthesis of 1,2-anti-diols.
N. Bajwa, M. P. Jennings, J. Org. Chem., 2008,
73, 3638-3641.
α-Keto esters can be prepared via Mannich addition of ethyl diazoacetate to
imines followed by oxidation of the diazo group with Oxone. Implementation of a
recently developed dynamic kinetic resolution of β-substituted-α-keto esters via
Ru(II)-catalyzed asymmetric transfer hydrogenation provides enantioenriched
anti-α-hydroxy-β-amino acid derivatives in high diastereo- and
enantioselectivity.
C. G. Goodman, D. T. Do, J. S. Johnson, Org. Lett., 2013,
15, 2446-2449.
An asymmetric α-alkylative reduction of prochiral ketones with primary
alcohols has been disclosed. The reaction is catalyzed by both iridium and
ruthenium complexes and gave optically active alcohols with elongation of
the carbon skeleton with high enantioselectivity.
G. Onodera, Y. Nishibayashi, S. Uemura, Angew. Chem. Int. Ed., 2006, 45, 3819-3822.
Carrots (Daucus carota) were used as cheap, eco-compatible, and efficient
reducing reagent for the conversion of cyclic amino-ketones into amino-alcohols
in high yields and enantiomeric excesses. The procedure allows an easy access to
precursors of biologically active products.
R. Lacheretz, D. G. Pardo, J. Cossy, Org. Lett., 2009,
11, 1245-1248.
An iridium-catalyzed, chemoselective, asymmetric transfer hydrogenation of α-substituted
acetophenones using formic acid as reductant can be performed in water and open
to air.
O. Soltani, M. A. Ariger, H. Vázquez-Villa, E. M. Carreira, Org. Lett., 2010,
12, 2893-2895.
(R)-β-Hydroxy nitriles were obtained via a reduction catalyzed by a
recombinant carbonyl reductase with excellent optical purity and were further
converted to (R)-β-hydroxy carboxylic acids via a nitrilase-catalyzed
hydrolysis. The present study allows ready access to both chiral β-hydroxy
nitriles and β-hydroxy carboxylic acids of pharmaceutical importance.
D. Zhu, H. Ankati, C. Mukherjee, Y. Yang, E. R. Biehl, L. Hua, Org. Lett., 2007,
9, 2561-2563.
A catalytic DKR-ATH process for the enantio- and diastereoselective reduction
of α-substituted-β-keto carbonitriles enables the simultaneous construction of
β-hydroxy carbonitrile scaffolds with two contiguous stereogenic centers in high
yields and excellent enantio- and diastereoselectivities.
F. Wang, T. Yang, T. Wu, L.-S. Zheng, C. Yin, Y. Shi, X.-Y. Ye, G.-Q. Chen, X.
Zhang, J. Am. Chem. Soc.,
2021, 143, 2477-2483.
Various enantiomerically pure α-hydroxy esters were synthesized by a Ru-Cn-Tunephos-catalyzed
asymmetric hydrogenation of α-keto esters. High enantiomeric excess has been
achieved for both α-aryl and α-alkyl substituted α-keto esters.
C.-J. Wang, X. Sun, X. Zhang, Synlett,
2006, 1169-1172.
An iridium-catalyzed hydrogenation of α-fluoro ketones provides β-fluoro
alcohols with good enantiomeric and diastereomeric selectivities using a
strategy of dynamic kinetic resolution. A C-FˇˇˇNa charge-dipole interaction in
the transition state of hydride transfer is responsible for the diastereomeric
control.
X. Tan, W. Zeng, J. Wen, X. Zhang,
Org. Lett., 2020, 22, 7230-7233.
The use dynamic kinetic resolution combined with asymmetric transfer
hydrogenation in water provides β-hydroxy-α-(tert-butoxycarbonyl)amino esters in
good yields, diastereoselectivities, and enantioselectivities. A surfactant is
employed to achieve good yields due to the hydrophobic nature of both the
catalyst and substrate.
B. Seashore-Ludlow, F. Seint-Dizier, P. Somfai, Org. Lett., 2012,
14, 6334-6337.
Related
A C2-symmetric copper-bound N-heterocyclic carbene (NHC)
exhibits excellent reactivity and enantioselectivity in the hydrosilylation of a
variety of structurally diverse ketones including challenging substrates as
2-butanone and 3-hexanone. Even at low catalyst loading (2.0 mol %), the
reactions occur in under an hour at room temperature and often do not require
purification beyond catalyst and solvent removal.
A. Albright, R. E. Gawley, J. Am. Chem. Soc., 2011,
133, 19680-19683.
The rhenium-catalyzed hydrosilation of aldehydes and ketones under ambient temperature and atmosphere gave protected alcohol as silyl ether in good yields. The mechanism is discussed.
E. A. Ison, E. R. Trivedi, R. A. Corbin, M. M. Abu-Omar, J. Am. Chem. Soc.,
2005, 127, 15374-15375.
Optimizations to generate CuH in situ have led to an efficient and inexpensive hydrosilylation method for dialkyl ketones.
B. H. Lipshutz, C. C. Caires, P. Kuipers, W. Chrisman, Org. Lett., 2003, 5, 3085-3088.
Aliphatic carboxyl derivatives (acids, acyl chlorides, esters) and aldehydes were efficiently reduced to the methyl group by HSiEt3
in the presence of catalytic amounts of B(C6F5)3. Aromatic carboxylic acids, as well as other carbonyl functional equivalents,
underwent smooth partial reduction to the corresponding TES-protected benzylic alcohols in competition with a Friedel-Crafts-like alkylation decreasing the overall
selectivity of the reduction process.
V. Gevorgyan, M. Rubin, J.-X. Liu, Y. Yamamoto, J. Org. Chem, 2000, 66, 1672-1675.
A formic acid promoted hydration of readily available alkynes followed by an
iridium-catalyzed transfer hydrogenation under mild conditions provides
alcohols. This transformation is simple, efficient, and can be performed with a
variety of alkynes in good yields and with excellent stereoselectivities.
N. Luo, Y. Zhong, J.-T. Liu, L. Ouyang, R. Luo, Synthesis, 2020, 52,
3439-3445.