Categories: C-O Bond Formation >
Synthesis of esters
Related: |
|
 |
 |
Name Reactions
Reactions
Decarboxylative Esterification
Protecting Groups
Benzyl esters
Recent Literature
Dimethylcarbonate is a nontoxic and green methylating reagent. A base-catalyzed
methyl transfer from dimethylcarbonate to carboxylic acids offers high
selectivity for esterification and mild reaction conditions, that enable
conservation of stereochemistry at epimerizable stereocenters. Isotope-labeling
studies suggest a mechanism via direct methyl transfer from dimethylcarbonate to
the substrate.
Y. Ji, J. Sweeney, J. Zoglio, D. J. Gorin, J. Org. Chem., 2013,
78, 11606-11611.
A Cu-catalyzed nondecarboxylative methylation of carboxylic acids with
methylboronic acid proceeds in air as sole oxidant and offers a strategy for
replacing toxic, electrophilic alkylating reagents. An isotope-labeling study
supports an oxidative cross-coupling mechanism, in analogy to that proposed for
Chan-Lam arylation.
C. E. Jacobson, N. Martinez-Muñoz, D. J. Gorin, J. Org. Chem.,
2015,
80, 7305-7310.
The one-electron electrochemical oxidation of TEMPO-Me produces a powerful
electrophilic methylating agent, that can be used for a methylation of aromatic
acids.
P. L. Norcott, C. L. Hammill, B. B. Noble, J. C. Robertson, A. Olding, A. C.
Bissembler, M. L. Coote, J. Am. Chem. Soc.,
2019,
141, 15450-15455.
A copper-catalyzed O-methylation of carboxylic acids using dimethyl sulfoxide
(DMSO) as the methyl source exhibits a broad substrate scope and excellent
functional group tolerance. Mechanistic studies indicate that a methyl radical
is generated from dimethyl sulfoxide.
J. Jia, Q. Jiang, A. Zhao, B. Xu, Q. Liu, W.-P. Luo, C.-C. Guo,
Synthesis, 2016, 48, 421-428.
Methyl salicylate is a selective and inexpensive methylating agent for the
esterification of carboxylic acids with a wide range of functional group
tolerance. The intramolecular hydrogen bonds between the carboxylate and
hydroxyl groups in methyl salicylate are essential for the transformation. Allyl,
benzyl, methallyl, and propargyl salicylates can also be used as alkylating
agents for the preparation of the corresponding alkyl carboxylates.
S. Chen, L. Jia, X. Li, M. Luo, Synthesis, 2014, 46,
263-268.
A continuous flow protocol for the diazotization of amines with
1,3-propanedinitrite in THF enables the synthesis of esters in high yields from
various carboxylic acids in 20 min at 90°C. The reaction conditions were
compatible with many functional groups, such as nitrogen-containing heterocycles,
alkynes, alkenes, alcohols, and phenols.
C. Audubert, H. Lebel, Org. Lett.,
2017, 19, 4407-4410.
Sulfuryl fluoride activates the carbonyl groups of amides as nucleophiles
while the activated hydroxyl groups of alcohols act as electrophiles. The amide
C-N bonds could be easily cleaved to form the ester C-O bonds at room
temperature without using transition metals. The reaction offers broad substrate
scope and excellent functional group compatibility.
W.-Y. Fang, G.-F. Zha, H.-L. Qin,
Org. Lett., 2019, 21, 8657-8661.
A very fast, microwave-assisted formation of carboxylic esters via reaction of carboxylic acids with O-alkylisoureas
derived from primary and secondary alcohols proceeds in good yields with clean inversion of configuration where appropriate.
The reaction works well with very hindered carboxylic acids.
A. Chighine, S. Crosignani, M.-C. Arnal, M. Bradley, B. Linclau, J. Org. Chem., 2009,
74, 4638-4641.
A. Chighine, S. Crosignani, M.-C. Arnal, M. Bradley, B. Linclau, J. Org. Chem., 2009,
74, 4638-4641.
Treatment of methylarenes with 1,3-dibromo-5,5-dimethylhydantoin or N-bromosuccinimide
and a catalytic amount of 2,2′-azobis(isobutyronitrile) followed by a reaction
with a nucleophile, such as benzoic acid, p-toluenethiol, sodium p-toluenesulfinate,
aqueous dimethylamine, or succinimide, provides the corresponding benzylated
products in good yields.
H. Shimojo, K. Moriyama, H. Togo, Synthesis, 2015, 47,
1280-1290.
Nucleophilic fluorination using CsF or alkali metal fluorides was completed in
short reaction time in the presence of [bmim][BF4] affording the
desired products without any byproducts. Facile nucleophilic substitutions such
as halogenations, acetoxylation, nitrilation, and alkoxylations in the presence
of ionic liquids provided the desired products in good yields.
D. W. Kim, C. E. Song, D. Y. Chi, J. Org. Chem., 2003, 68,
4281-4285.
Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents
for nucleophilic substitution reactions of sulfonate esters derived from primary
and secondary alcohols. The newly developed protocol is very environmentally
attractive because the reactions use stoichiometric amounts of ionic liquids as
sole reagents without additional solvents and activating reagents. Moreover,
these ionic liquids can be readily recycled.
Y. Liu, Y. Xu, S. H. Jung, J. Chae, Synlett, 2012, 23,
2663-2666.
A highly effective synthesis of methyl esters from benzylic alcohols, aldehydes,
or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide
is easily accessible and practical and offers an alternative to the traditional
way.
Y. Zhu, H. Yan, L. Lu, D. Liu, G. Rong, J. Mao, J. Org. Chem., 2013,
78, 9898-9905.
An efficient arylation of carboxylic acids with diaryliodonium salts gives aryl
esters in high yields within short reaction times for both aromatic and
aliphatic substrates. The transition-metal-free conditions are compatible with a
range of functional groups, and good chemoselectivity is observed with
unsymmetric diaryliodonium salts. Furthermore, steric hindrance in the ortho
positions is well tolerated.
T. B. Petersen, R. Khan, B. Olofsson, Org. Lett., 2011,
13, 3454-3457.
A mild and efficient intermolecular addition of phenols and carboxylic acids
to olefins is catalyzed by Ph3PAuOTf.
C.-G. Yang, C. He, J. Am. Chem. Soc.,
2005,
127, 6966-6967.
A direct catalytic anti-Markovnikov addition of carboxylic acids to alkenes is
comprised of the Fukuzumi acridinium photooxidant and a substoichiometric
quantity of a hydrogen-atom donor. Oxidizable olefins, such as styrenes,
trisubstituted aliphatic alkenes, and enamides, can be employed along with a
variety of carboxylic acids to afford the anti-Markovnikov addition adducts
exclusively.
A. J. Perkowski, D. A. Nicewicz, J. Am. Chem. Soc., 2013,
135, 10334-10337.
An efficient two-step protocol that employs readily available terminal alkenes
as starting materials enables a highly regio- and stereoselective synthesis of
various allylic acetates. This method affords linear (E)-isomers and
tolerates several functional groups including halogen-containing molecules. For
other weak oxygen, carbon, nitrogen, and sulfur nucleophiles, adducts were
obtained in very good yields too.
X. Huang, B. Fulton, K. White, A. Bugarin, Org. Lett.,
2015,
17, 2594-2597.
The presence of a base strongly improves the efficiency and the selectivity of
the Pd-catalyzed oxidation of terminal alkenes in carboxylic acids. The
methodology is particularly well adapted for the oxidation of homoallylic
alcohols, for which the resulting acyloxylated products are obtained selectively
as E-isomers in good yields.
E. Thiery, C. Aouf, J. Belloy, D. Harakat, J. Le Bras, J. Muzart, J. Org. Chem., 2010,
75, 1771-1774.
An oxidative decarboxylation of β,γ-unsaturated carboxylic acids mediated by
PhI(OAc)2 gives the corresponding allylic acetates. In addition, a
decarboxylative C-N bond formation was achieved. Mechanistic studies suggest an
unique reactivity of hypervalent iodine reagents in this ionic oxidative
decarboxylation.
K. Kiyokawa, S. Yahata, T. Kojima, S. Minakata, Org. Lett.,
2014,
16, 4646-4649.
The combination of [Ru(p-cymene)Cl2]2/triethylphosphine/lithium
carbonate catalyzes a coupling of aryl bromides with unprotected 2-arylacrylic
acids to form (Z)-diarylacrylic acids in high yields. The reaction
tolerates a wide range of functional groups. The vinylic C-H activation proceeds
via base-assisted cyclometalation rather than a Heck-type mechanism, which
explains its stereoselectivity.
F. Belitz, A.-K. Seitz, J. F. Goebel, Z. Hu, L. K. Goossen, Org. Lett.,
2022, 24, 3467-3470.
A method for the preparation of a wide range of branched allylic esters from
terminal alkynes proceeds via a redox-neutral propargylic CH activation
employing a rhodium(I)/DPEphos catalyst.
A. Lumbroso, P. Koschker, N. R. Vautravers, B. Breit, J. Am. Chem. Soc., 2011,
133, 2386-2389.
A photocatalytic decarboxylation of α,β-unsaturated acids followed by a C-O
cross-coupled esterification provides α-oxycarbonyl-β-ketones. Water as the
source of oxygen for the ketone segment and aerial oxygen as an oxidant make the
present dual Ir/Pd-catalytic methodology green and sustainable.
S. Mondal, S. Mondal, S. P. Midya, S. Das, S. Mondal, P. Ghosh, Org. Lett., 2023, 25,
184-189.
A rhodium-catalyzed N-H and O-H insertion of amides and carboxylic acids
with α-diazo-β-ketoesters gives different α-amido- and
α-carboxylic-β-ketoesters in good yields. The reactions were performed under
mild conditions with 1 mol% of catalyst.
S. Bertelsen, M. Nielsen, S. Bachmann, K. A. Jorgensen,
Synthesis, 2005, 2234-2238.
Nonbenzenoid aromatic carbocation can be used as organic
Lewis acid catalysts in O-H functionalization reactions of diazoalkanes with
benzoic acids. The reported protocol with tropylium is applicable to a wide range of
diazoalkanes and carboxylic acids with excellent efficiency.
C. Empel, T. V. Nguyen, R. M. Koenigs, Org. Lett., 2021, 23,
548-553.
Functionalization of carboxylic acids with sulfoxonium ylides in the presence
of [VO(acac)2] provides α-carbonyloxy esters in good yield. Diazo
compounds as usual carbene source failed.
F. F. Koothradan, A. S. Babu, K. P. Pushpakaran, A. Jayarani, C. Sivasankar, J. Org. Chem., 2022, 87,
10564-10575.
"Activated" dimethyl sulfoxide efficiently dehydrogenates hydrazones to the
respective diazo compounds at -78°C. Under optimized conditions, simple vacuum
filtration provides solutions of pure diazo compounds from which stable diazo
species can be isolated in high yield, or that can be directly used in
subsequent reactions.
M. I. Javed, M. Brewer, Org. Lett., 2007,
9, 1789-1792.
0.01 mol-% Zinc(II) salts catalyze the reaction between acetals and acid halides to
provide haloalkyl ethers in near-quantitative yield in 1 - 4 h. The
solutions of haloalkyl ethers can be utilized directly in
reactions in which the presence of the ester byproduct does not interfere.
Excess carcinogenic haloalkyl ether is destroyed on workup.
M. A. Berliner, K. Belecki, J. Org. Chem., 2005,
70, 9618-9621.
A Cu(OTf)2-mediated Chan-Lam reaction of carboxylic acids with
arylboronic acids is a facile and practical methodology to access phenolic
esters in good yields. The procedure tolerates various functional groups, such
as methoxycarbonyl, acetoxy, free phenolic hydroxyl, vinyl, nitro,
trifluoromethyl, methoxyl, bromo, chloro, iodo, and acetyl groups.
L. Zhang, G. Zhang, M. Zhang, J. Cheng, J. Org. Chem., 2010,
75, 7472-7474.
An efficient, mild and transition-metal-free N-arylation of amines,
sulfonamides, and carbamates and O-arylation of phenols and carboxylic acids has
been achieved by using various o-silylaryl triflates in the presence of CsF.
Z. Liu, R. C. Larock, J. Org. Chem., 2006,
71, 3198-3209.
Various anilides have been directly ortho-acetoxylated with acetic acid as the acetate
source and K2S2O8 as the oxidant in the
presence of
Pd(OAc)2 as catalyst. The amide group is an elegant directing group to convert aromatic sp2 C-H bonds into C-O bonds.
G.-W. Wang, T.-T. Yuan, X.-L. Wu, J. Org. Chem., 2008,
73, 4717-4720.
A mild copper-catalyzed Chan-Lam-Evans type cross-coupling reaction enables a
stereospecific and regioselective preparation of enol esters from carboxylate
salts or carboxylic acids and potassium alkenyltrifluoroborate salts in the
presence of oxygen, catalytic CuBr, DMAP and 4 Å molecular sieves. Overall, this
method demonstrates carboxylic acids as suitable reaction partners for
nondecarboxylative copper-catalyzed cross-couplings.
F. Huang, T. D. Quach, R. A. Batey, Org. Lett., 2013,
15, 3058-3061.
A rhodium-catalyzed, selective intermolecular anti-Markovnikov addition
of carboxylic acids to terminal alkynes gives valuable Z-enol esters. The
catalyst system is applicable to a broad substrate scope and displays a wide
functional group tolerance.
A. Lumbroso, N. R. Vautravers, B. Breit, Org. Lett., 2010,
12, 5498-5501.
Ruthenium complexes were successfully applied in highly regioselective
Markovnikov additions of carboxylic acids to terminal alkynes, yielding valuable
enol esters. Selectivity and activity could be further improved by the addition
of catalytic amounts of AgOTf. A broad range of simple as well as electronically
or sterically challenging substrates could be isolated in good to excellent
yields with high regioselectivity and under mild reaction conditions.
J. Jeschke, C. Gäbler, H. Lang, J. Org. Chem.,
2016,
81, 476-484.
A cobalt-catalyzed highly regio- and stereoselective hydro-oxycarbonylation
of terminal and internal alkynes with carboxylic acids provides enol esters in
high yields. A catalyst in situ generated from Co(BF4)2, a
tridentate phosphine ligand, and zinc exhibits a higher reactivity than the
corresponding cobalt/diphosphine complex.
J.-F. Chen, C. Li, Org. Lett.,
2018, 20, 6719-6724.
PPh3AuCl/AgPF6-catalyzed hydroacyloxylation of alkynes
with carboxylic acids affords the Markonikov addition products, whereas PPh3AuCl/AgOTf
catalyst gives the more stable isomerized products via the Markonikov products.
B. C. Chary, S. Kim, J. Org. Chem., 2010,
75, 7928-7931.
A gold(I)-catalyzed rearrangement of diversely substituted allenyl carbinol
esters allows the efficient, rapid, and stereoselective synthesis of various
functionalized 1,3-butadien-2-ol esters via a new 1,3-shift of an ester moiety
onto a gold-activated allene.
A. K. Buzas, F. M. Istrate, F. Gagosz, Org. Lett., 2007,
9, 985-988.
The preparation of diverse β-chloroethers, β-chloroacetates, and
chlorohydrins is efficiently achieved under mild conditions by reaction of
alkenes with trichloroisocyanuric acid in alcohols, acetic acid or aqueous
acetone, respectively.
G. Fonseca Mendonça, A. Manzolillo Sanseverino, M. C. S. de Mattos, Synthesis,
2003, 45-48.
A new palladium-catalyzed method allows the oxygenation of unactivated sp3
C-H bonds of a wide variety of alkane substrates containing readily
available oxime and/or pyridine directing groups with extremely high levels
of chemo-, regio-, and in some cases diastereoselectivity.
L. V. Desai, K. L . Hull, M. S. Sanford, J. Am. Chem. Soc.,
2004,
126, 9542-9543.