Categories: C-C Bond Formation > Heteroatom-containing Molecules, Chains > Trifluoromethylation
Synthesis of trifluoromethyl alkenes
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Recent Literature
Tri(9-anthryl)borane catalyzes a visible-light-induced trifluoromethylation
of unactivated alkenes with CF3I. The mild reaction conditions
tolerate various functional groups, and the reaction could be extended to
perfluoroalkylations with C3F7I and C4F9I.
J. Moon, Y. K. Moon, D. D. Park, S. Choi, Y. You, E. J. Cho, J. Org. Chem., 2019, 84,
12925-12932.
A method for trifluoromethylation of alkenes uses visible light photoredox
catalysis with CF3I, Ru(Phen)3Cl2, and DBU.
This process works especially well for terminal alkenes to give alkenyl-CF3
products with only E-stereochemistry and tolerates various functional
groups.
N. Iqbal, S. Choi, E. Kim, E. J. Cho, J. Org. Chem., 2012,
77, 11383-11387.
Fluoride ions induce a cross-coupling reaction of organic halides with
trifluoromethyltrialkylsilanes in the presence of Cu(I) salts under mild
reaction conditions to provide the corresponding trifluoromethylated products in
good yields.
H. Urata, T. Fuchikami, Tetrahedron Lett., 1991,
32, 91-94.
A formal hydrotrifluoromethylation of alkynes is achieved via
hydroboration/trifluoromethylation using the inexpensive fluoroform-derived
[CuCF3] reagent. Synthetically useful (E)-alkenyl-CF3
building blocks and 1,1-bis(trifluoromethyl)-substituted alkenes can be prepared
under ambient conditions in one pot/one step from alkynes.
L. He, X. Yang, G. C. Tsui, J. Org. Chem.,
2017, 82, 6192-6201.
The use of a Cu(III)-CF3 reagent and a silane enables an efficient
and selective hydro-trifluoromethylation of terminal alkynes in DMF to provide
1,2-disubstituted trifluoromethylated Z-alkenes. The unusual Z-selectivity
and the compatibility of various functional groups make this reaction
complementary to previously reported methods producing predominantly E-products.
S.-L. Zhang, C. Xiao, J. Org. Chem., 2018, 83,
10908-10915.
An electro-oxidative strategy enables an efficient decarboxylative
trifluoromethylation of α,β-unsaturated carboxylic acids using the Langlois
reagent as a trifluoromethyl precursor. Under catalyst-free and external
oxidant-free conditions, a series of trifluoromethylated styrenes are obtained
with a high regioselectivity in good yields.
H. Hong, Y. Li, L. Chen, B. Li, Z. Zhu, X. Chen. L. Chen, Y. Huang, J. Org. Chem., 2019, 84,
5980-5986.
A copper-catalyzed decarboxylative trifluoromethylation of various
α,β-unsaturated carboxylic acids was achieved by using a stable and inexpensive
solid, sodium trifluoromethanesulfinate (CF3SO2Na,
Langlois reagent). In addition, an iron-catalysis enables a difluoromethylation
of aryl-substituted acrylic acids by using zinc difluoromethanesulfinate (DFMS,
(CF2HSO2)2Zn, Baran reagent) via a similar
radical process.
Z. Li, Z. Cui, Z.-Q. Liu, Org. Lett., 2013,
15, 406-409.
A copper(I)-catalyzed, regioselective C-H α-trifluoromethylation of
α,β-unsaturated carbonyl compounds as well as α,β-unsaturated esters, thioesters,
and amides using Togni’s reagent afforded the corresponding (E)-α-trifluoromethylated
products in good yields.
Z. Fang, Y. Ning, P. Mi, P. Liao, X. Bi, Org. Lett., 2014,
16, 1522-1525.
A novel domino copper-catalyzed trifluoromethylated Meyer-Schuster rearrangement
reaction with Togni’s reagent provides α-trifluormethyl enones with moderate to
good yields. Furthermore, these α-CF3 enones can be transformed
toward interesting trifluoromethyl-substituted heterocycles in a one-pot
reaction.
Y.-P. Xiong, M.-Y. Wu, X.-Y. Zhang, C.-L. Ma, L. Huang, L.-J. Zhao, B. Tan,
X.-Y. Liu, Org. Lett., 2014,
16, 1000-1003.
An ammonium hydrogen-bonding-assisted α-F elimination from Cu-CF3
compounds generates R3N·HF reagents in situ. This strategy enables a
dual fluorination and trifluoromethylation of terminal alkynes in the presence
of a single Cu(III)-CF3 compound and a tertiary amine with excellent
regio- and stereoselectivity.
S.-L. Zhang, J.-J. Dong,
Org. Lett., 2019, 21, 6893-6896.
The collaboration of (phen)CuIII(CF3)3 and
CsF enables a one-step concurrent fluoro-trifluoromethylation across the triple
bond of arylacetylenes in a syn mode to provide chemo-, regio-, and
stereoselectively (Z)-α-fluoro-β-CF3 styrenes. This method can be
extended to achieve syn-oxy-trifluoromethylation and syn-aryl-trifluoromethylation.
S.-L. Zhang, H.-X. Wan, W.-F. Bie, Org. Lett.,
2017, 19, 6372-6375.
Cu(CH3CN)4BF4 catalyzes a radical
bis(trifluoromethylation) of alkynes and 1,3-enynes with Togni reagent II and
(bpy)Zn(CF3)2 at room temperature to afford the
corresponding 1,2-bis(trifluoromethylated) alkenes and
1,4-bis(trifluoromethylated) allenes in good yields. This protocol exhibits
broad substrate scope and excellent functional group compatibility.
H. Shen, H. Xiao, L. Zhu, C. Li, Synlett, 2020,
31,
41-44.
Related
A nickel-catalyzed alkylation/arylation of 1-chloro-3,3,3-trifluoroprop-1-ene
(HCFO-1233zd) with alkyl/aryl zinc reagents and a cobalt-catalyzed reductive
cross-coupling between HCFO-1233zd and aryl bromides provide
1-(trifluoromethyl)alkenes. These approaches feature broad substrate scope, high
functional group tolerance, and the use of industrial feedstocks and low-cost Ni
or Co catalysts.
W. Zhou, Q.-W. Zhao, Y.-C. Luo, X. Zhang, Synthesis, 2023,
55, 1844-1854.
An efficient Pd-catalyzed stereoselective vinyltrifluoromethylation of aryl
halides, through decarboxylative cross-coupling with 2-(trifluoromethyl)acrylic
acid offers ready availability of the starting materials, high level of
functional group tolerance, and excellent E/Z selectivity. This
protocol is a safe and operationally convenient strategy for an efficient
synthesis of vinyltrifluoromethyl derivatives.
S. Kathiravan, I. A. Nicholls, Org. Lett.,
2015,
17, 1874-1877.
A Pd-catalyzed hydrogenation of potassium
(3,3,3-trifluoroprop-1-yn-1-yl)trifluoroborate provides either the (Z)-
or (E)-isomer of the vinylborate in >98% purity. Coupling with bromo- and
iodoarenes provides a variety of (Z)- or (E)-β-trifluoromethylstyrenes.
Also, a safe synthesis of the alkynyltrifluoroborate has been described.
P. V. Ramachandran, W. Mitsuhashi, Org. Lett.,
2015,
17, 1252-1255.
An operationally simple, inexpensive, and rapid route for the olefination of a
wide array of trifluoromethyl ketones using a Peterson olefination approach
gives very good yields of 3,3,3-trifluoromethylpropene products and can be
performed without purification of the β-hydroxysilyl intermediate. The reaction
can be extended to other perfluoroalkyl substituents and is easily scaled up.
T. A. Hamlin, C. B. Kelly, R. M. Cywar, N. E. Leadbeater, J. Org. Chem., 2014,
79, 1145-1155.