Versatile Cross Coupling Methods:
Hiyama Coupling (R-X + R'-SiR''3)
Hiyama-Denmark Coupling (R-X + R-SiMe2OH)
Kumada Coupling (R-X + R'-MgX)
Negishi Coupling (R-X + R'-ZnX)
Stille Coupling (R-X + R'-SnR''3)
Suzuki Coupling (R-X + R'-BY3)
A general and mild protocol of oxygen-promoted Pd(II) catalysis allows a selective cross-couplings of alkenyl- and arylboron compounds with various olefins. Unlike most cross-coupling reactions, this new methodology works well even in the absence of bases, consequently averting undesired homo-couplings.
K. S. Yoo, C. H. Yoon, J. W. Jung, J. Am. Chem. Soc., 2006, 128, 16348-16393.
A mild and efficient Pd(II) catalysis leads to the formation of carbon-carbon bonds between various organoboron compounds and alkenes. The resultant Pd(0) species is reoxidized by molecular oxygen to Pd(II). This protocol promotes the desired Pd(II) catalysis, whereas the competing Pd(0) pathways (Heck or Suzuki) are retarded.
Y. C. Jung, R. K. Mishra, C. H. Yoon, K. W. Jung, Org. Lett., 2003, 5, 2231-2234.
In Suzuki-Miyaura coupling, Z-alkenyl halides can easily undergo Z-to-E isomerization, the extent of which is dictated mainly by the ligand on palladium. Pd(P(o-Tol)3)2 as catalyst of choice leads to the desired products under mild conditions and in high yields that, in most cases, retain their Z-olefin geometry.
G.-P. Lu, K. R. Voigtritter, C. Cai, B. H. Lipshutz, J. Org. Chem., 2012, 77, 3700-3703.
A base-free rhodium-catalyzed Mizoroki-Heck reaction of potassium aryltrifluoroborates with alkenes in the presence of acetone as green "oxidant" constitutes an interesting alternative to conventional olefinations using aryl halides thanks to the ready availability of organoboranes.
R. Martinez, F. Voica, J.-P. Genet, S. Darses, Org. Lett., 2007, 9, 3213-3216.
The use of the σ-donating DMA solvent is crucial for high selectivity in a simple, mild, and efficient Pd-catalyzed Heck reaction, that delivers (E)-styrenyl products for electronically nonbiased olefin substrates bearing a range of useful functionality in high yields. Further studies suggest that the catalyst distinguishes between β-hydrogens on the basis of their relative hydridic character.
E. W. Werner, M. S. Sigman, J. Am. Chem. Soc., 2011, 133, 9692-9695.
Aryl Grignard reagents react stereospecifically with alkenyl halides in the presence of manganese chloride as catalyst to afford cross-coupled products in good yields.
G. Cahiez, O. Gager, F. Lecomte, Org. Lett., 2008, 10, 5255-5256.
A direct cobalt-catalyzed vinylation of various aromatic halides using β-halostyrene proceeded smoothly with a total retention of the double bond configuration in the presence of triphenylphosphine as ligand. This procedure offers a new route to the stereoselective synthesis of functionalized stilbenes.
A. Moncomble, P. Le Floch, A. Lledos, C. Gosmini, J. Org. Chem., 2012, 77, 5056-5062.
The presence of FeCl3/CuTC enables an efficient coupling of functionalized aryl Grignard reagents and 1-arylvinyl halides to access 1,1-diarylethylenes of biological interest. This bimetallic system proved to be superior to the use of Fe or Cu catalyst alone. The synthetic utility of this protocol is illustrated in the field of steroid chemistry.
A. Hamze, J.-D. Brion, M. Alami, Org. Lett., 2012, 14, 2782-2785.
Rhodium-catalyzed regioselective arylzincation of terminal allenes affords synthetically useful functionalized allylzinc reagents, which can be protonated or react with various electrophiles such as carbonyl compounds and acetonitrile.
Y. Yoshida, K. Murakami, H. Yorimitsu, K. Oshima, J. Am. Chem. Soc., 2010, 132, 8878-8879.
Pd(OAc)2 in the presence of a BIAN ligand is an efficient catalyst system for the base-free oxidative Heck reaction that outperforms the currently available catalysts for the more challenging substrates studied. The catalyst system is highly selective, and works at room temperature with dioxygen as the oxidant.
A. L. Gottumukkala, J. F. Teichert, D. Heijnen, N. Eisink, S. van Dijk, C. Ferrer, A. van den Hoogenband, A. J. Minnaard, J. Org. Chem., 2011, 76, 2937-2941.
In the TMSOTf-mediated catalytic carbocupration of ynoates, catalyst loadings as low as 5 mol % readily allow for high yields and diastereoselectivities for a series of aromatic Grignard reagents. A vicinally functionalization is possible via initial TMSOTf-mediated catalytic carbocupration followed by a secondary electrophilic capture of the TMS allenoate intermediate.
A. J. Mueller, M. P. Jennings, Org. Lett., 2007, 9, 5327-5329.
An (E)- and (Z)-stereocomplementary preparative method for α,β-disubstituted α,β-unsaturated esters is performed via three general and robust reaction sequences: Ti-Claisen condensation (formylation) of esters to give α-formyl esters, (E)- and (Z)-stereocomplementary enol tosylation using TsCl-N-methylimidazole-Et3N and LiOH, and stereoretentive Suzuki-Miyaura cross-coupling.
H. Nakatsuji, H. Nishikado, K. Ueno, Y. Tanabe, Org. Lett., 2009, 11, 4258-4261.
A mild and efficient protocol for palladium-catalyzed oxidative Heck reactions of arylboronic acids with both electron-rich and -deficient olefins works in the absence of a base, oxygen, or other external oxidants. With a wide variety of substrates tolerated, the method broadens the scope of palladium-catalyzed coupling reactions.
J. Ruan, X. Li, O. Saidi, J. Xiao, J. Am. Chem. Soc., 2008, 130, 2424-2425.
Aryl nonaflates are employed as electrophiles in the Pd-catalyzed cross-coupling with tosylhydrazones affording highly substituted olefins. Addition of LiCl and the presence of small amounts of water are required to accomplish the coupling successfully. Under the optimized conditions, the reactions proceed with high yield and also high stereoselectivity depending on the nature of the coupling partners.
J. Barluenga, L. Florentino, F. Aznar, C. Valdes, Org. Lett., 2011, 13, 510-513.
A Pd-catalyzed oxidative cross-coupling reaction of arylboronic acids with α-diazoesters using molecular oxygen as the reoxidant gives E-α,β-diarylacrylates in good yields and very high E-to-Z selectivity.
Y.-T. Tsoi, Z. Zhou, A. S. C. Chan, W.-Y. Yu, Org. Lett., 2010, 12, 4506-4509.
Arylations of electron-rich heteroatom-substituted olefins were performed with electron-rich arylboronic acids via palladium(II) catalysis. This mild protocol, which offers access to functionalized enamides, exploits oxygen gas for reoxidation and a stable 1,10-phenanthroline bidentate ligand to promote the palladium(II) regeneration and to control the regioselectivity.
M. M. S. Andappan, P. Nilsson, H. v. Schenck, M. Larhed, J. Org. Chem., 2004, 69, 5212-5218.
The palladium-catalyzed cross-coupling reaction of potassium vinyltrifluoroborate with aryl electrophiles can generally be effected using 2 mol % of PdCl2 and 6 mol % of PPh3 as a catalyst system in THF/H2O with Cs2CO3 as a base. Good yields are obtained in the presence of various functional groups.
G. A. Molander, A. R. Brown, J. Org. Chem., 2006, 71, 9681-9686.
A Pd(0)-catalyzed Suzuki-Miyaura coupling reaction of aryl boronic acids with vinyl tosylate provides access to styrene derivatives in good yields. The easily accessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology was expanded using the similar and also readily available 2,2-difluorovinyl tosylate.
T. M. Gøgsig, L. S. Søbjerg, A. T. Lindhardt (neé Hansen), K. L. Jensen, T. Skrydstrup, J. Org. Chem., 2008, 73, 3404-3410.
A variety of aromatic iodides and bromides undergo cross-coupling with divinyltetramethyldisiloxane (DVDS) to give styrenes in good yields in the presence of potassium trimethylsilanoate and catalytic amounts of Pd(dba)2. Triphenylphosphine oxide is needed to extend catalyst lifetime.
S. E. Denmark, C. R. Butler, J. Am. Chem. Soc., 2008, 130, 3690-3704.
Fluoride-free cross-coupling reactions of alkenyltrialkoxysilanes with aryl iodides, bromides, and chlorides are performed under ligand-free conditions with low Pd loadings on water using sodium hydroxide as activator and tetra-n-butylammonium bromide as additive at 120°C under conventional or microwave heating.
E. Alacid, C. Nájera, J. Org. Chem., 2008, 73, 2315-2322.
A novel bis-phenanthryl N-heterocyclic carbene (NHC) based palladium acetate catalyst was effective for the coupling of various aryl and vinyl chlorides with organoboron compounds. Hindered tri- and tetra-ortho substituted products were efficiently produced. Benzyl chloride was also found to be a useful coupling partner and trimethylboroxine was used to give methylated products.
C. Song, Y. Ma, Q. Chai, C. Ma, W. Jiang, M. B. Andrus, Tetrahedron, 2005, 61, 7438-7446.
Efficient, stereospecific palladium(0)-catalyzed Suzuki-Miyaura cross-couplings of potassium aryl- and heteroaryltrifluoroborates with alkenyl bromides can generally be carried out using 2 mol % of palladium catalyst and 3 equiv of base in toluene/H2O.
G. A. Molander, T. Fumagalli, J. Org. Chem., 2006, 71, 5743-5747.
A ruthenium-catalyzed chelation-assisted C-H bond activation of aromatic ketones followed by reaction with olefins provides Heck-type products in good to excellent yields with a high regio- and stereoselective manner.
K. Padala, M. Jeganmohan, Org. Lett., 2011, 13, 6144-6147.
Ruthenium-catalyzed oxidative C-H bond formation of N-methoxybenzamides using an oxidizing directing group gives ortho-substituted Heck-type products with acrylates in MeOH, whereas reactions with styrene (or norbornadiene) in CF3CH2OH affords 3,4-dihydroisoquinolinones.
B. Li, J. Ma, N. Wang, H. Feng, S. Xu, B. Wang, Org. Lett., 2012, 14, 736-739.
A novel chelate-controlled intermolecular oxidative Heck reaction proceeds with a wide range of nonresonance stabilized α-olefin substrates and organoboron reagents to afford internal olefin products in good yields and outstanding regio- and E:Z stereoselectivities. Pd-H isomerization, common in many Heck reactions, is not observed under these mild, oxidative conditions.
J. H. Delcamp, A. P. Brucks, M. C. White, J. Am. Chem. Soc., 2008, 130, 11270-11271.
Addition of arylmagnesium bromides to aryl(alkyl)acetylenes gave high yields of the corresponding alkenylmagnesium reagents in the presence of an iron catalyst and a N-heterocyclic carbene ligand. Subsequent treatment with electrophiles allows the formation of tetrasubstituted alkenes.
T. Yamagami, R. Shintani, E. Shirakawa, T. Hayashi, Org. Lett., 2007, 9, 1045-1048.
With certain substituent patterns, benzyl benzyl sulfone systems give unexpectedly high Z-stereoselectivity in the Meyers variant of the Ramberg-Bäcklund reaction. A range of sulfones were explored to rationalize this unprecedented selectivity for Z-stilbene systems.
J. S. Foot, G. M. P. Giblin, A. C. Whitwood, R. J. K. Taylor, Org. Biomol. Chem., 2005, 3, 756-763.
Palladium-catalyzed cross-coupling reaction of 1,1-diboryl-1-alkenes with aryl and alkenyl iodides proceeded stereoselectively to the corresponding mono-coupled product as a single diastereomer. A subsequent coupling with another aryl iodide afforded various triarylalkenes in their stereochemically pure form.
M. Shimizu, C. Nakamaki, K. Shimono, M. Schelper, T. Kurahashi, T. Hiyama, J. Am. Chem. Soc., 2005, 127, 12506-12507.
Palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts were performed at room temperature, without added base, under aerobic conditions using a thiourea-based C2-symmetric ligand. The reactions produced product in 4 h in good yield.
M. Dai, B. Liang, C. Wang, J. Chen, Z. Yang, Org. Lett., 2004, 6, 221-224.
A Pd(0)-catalyzed cross-coupling reaction of diazirines with aryl halides under microwave irradiation affords substituted olefins in good yields via a migratory insertion of a Pd carbene intermediate.
H. Jiang, H. Huang, H. Cao, C. Qi, Org. Lett., 2010, 12, 5561-5563.
PdCl2(MeCN)2 in combination with dppp is an efficient catalyst for the coupling of sterically hindered N-arylsulfonylhydrazones with aryl halides providing a flexible and convergent access to tetrasubstituted olefins related to iso-combretastatin A4 in good yields.
E. Brachet, A. Hamze, J.-F. Peyrat, J.-D. Brion, M. Alami, Org. Lett., 2010, 12, 4042-4045.
TsCl coupled with NMI forms a highly reactive N-sulfonylammonium intermediate. β-Ketoesters undergo (E)-selective tosylation using TsCl-NMI-Et3N and (Z)-selective tosylation using TsCl-NMI-LiOH in good yield. Stereoretentive Negishi and Sonogashira couplings using enol tosylates proceed successfully to give trisubstituted α,β-unsaturated esters.
H. Nakatsuji, K. Ueno, T. Misaki, Y. Tanabe, Org. Lett., 2008, 10, 2131-2134.
The employment of hydrophobic ionic liquids dramatically enhanced the activity of metal triflates in Friedel-Crafts alkenylations of aromatic compounds with various alkyl- and aryl-substituted alkynes.
C. E. Song, D.-U. Jung, S. Y. Choung, E. J. Roh, S.-G. Lee, Angew. Chem., 2004, 116, 6309-6311.
A variety of organolithiums are added to terminal and 2,2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highly stereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure.
D. M. Hodgson, M. J. Fleming, S. J. Stanway, J. Org. Chem., 2007, 72, 4763-4773.
A stereoselective arylation and vinylation of alkenes without transition-metal catalysts takes place through an interesting NBS-promoted semipinacol rearrangement under mild conditions and a subsequent unusual NaOH-mediated Grob fragmentation.
D.-Y. Yuan, Y.-Q. Tu, C.-A. Fan, J. Org. Chem., 2008, 73, 7797-7799.
The PdCl2/PtBu3 catalytic system with copper(I) iodide and cesium fluoride in DMF is most effective for coupling aryl bromides, while Pd(PPh3)4 is optimal when coupling iodides and triflates. The combination of copper(I) iodide and cesium fluoride should allow the synthesis of sterically hindered systems and promotes electronically disfavored coupling reactions.
S. P. H. Mee, V. Lee, J. E. Baldwin, Angew. Chem. Int. Ed., 2004, 43, 1132-1136.
A Pd(PPh3)4-catalyzed reaction between α-diazocarbonyl compounds and arylboronic acids leads to cross-coupled products in good yields.
C. Peng, Y. Wang, J. Wang, J. Am. Chem. Soc., 2008, 130, 1566-1567.
A regio- and stereoselective rhodium-catalyzed reaction of propargylic alcohols with boronic acids enables the synthesis of trisubstituted allylic alcohols. The utility of these synthons is demonstrated in a convenient synthesis of indenes and quinolines.
J. Panteleev, R. Y. Huang, E. K. J. Lui, M. Lautens, Org. Lett., 2011, 13, 5314-5317.
Cycloadditions of Diels-Alder dienophiles containing linked enyne sites, each substituted with activating groups, occurred specifically at the acetylenic center. A remote acrylyl group bound to the olefinic site totally dominated the regiochemical course of the cycloaddition. Explanations for these findings at the computational level are provided.
M. Dai, D. Sarlah, M. Yu, S. J. Danishefsky, G. O. Jones, K. N. Houk, J. Am. Chem. Soc., 2007, 129, 645-657.
Air-stable palladium complexes with phosphinous acid ligands serve as efficient catalysts for various cross-coupling reactions of vinyl and aryl chlorides with arylboronic acids, arylzinc reagents, and thiols.
G. Y. Li, J. Org. Chem., 2002, 67, 3643-3650.
The reaction of organocerium reagents, generated in situ from aryl and heteroaryl lithium compounds, with cycloalkanones proceeds cleanly to provide alkoxides. Addition of MsCl or SOCl2 with DBU gave aryl-substituted cycloalkenes in good yields. A short total synthesis of (±)-laurokamurene B is described.
J. Tallineau, G. Bashiardes, J.-M. Coustard, F. Lecornué, Synlett, 2009, 2761-2764.
Highly reactive zinc metal was readily prepared by electrolysis of a DMF solution containing naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. This reactive zinc was used for efficient transformation of ethyl 2-bromoacrylate into the corresponding organozinc compound, which was reacted with various aryl iodides in the presence of palladium catalyst to give ethyl 2-arylpropenoates in high yields.
A. A. Jalil, N. Kurono, M. Tokuda, Synthesis, 2002, 2681-2686.
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.
N-Vinylpyridinium and -trialkylammonium tetrafluoroborate salts represent a new class of electrophilic coupling partner for Pd(0)-catalyzed Suzuki cross-coupling reactions with various boronic acids in high yields. The crystalline, air-stable, and nonhygroscopic salts are easily prepared from activated acetylenes and pyridinium or trialkylammonium tetrafluoroborates.
K. R. Buszek, N. Brown, Org. Lett., 2007, 9, 707-710.
Lewis-acid catalysts such as AlMe3, AlMe2Cl, and BPh3 significantly improve the efficiency of the nickel-catalyzed aryl- and alkenylcyanation of alkynes. Electron-rich cyanides, which exhibit poor reactivity in the absence of Lewis acids, readily undergo the arylcyanation reaction under the newly disclosed conditions.
Y. Nakao, A. Yada, S. Ebata, T. Hiyama, J. Am. Chem. Soc., 2007, 129, 2428-2429.
(E)- or (Z)-trisubstituted α,β-unsaturated esters have been prepared in three steps from N-protected glycine. The key step is the highly selective enol tosylation of γ-amino β-keto esters followed by an effective Suzuki-Miyaura coupling reaction with a variety of aryl boronic acids.
J. Baxter, D. Steinhuebel, M. Palucki, I. W. Davies, Org. Lett., 2005, 7, 215-218.
1,1-diarylpropadienes and 1,3-diarylpropynes can be prepared by the sequential lithiation of 1-aryl-1-propynes, transmetalation, and the corresponding Pd(0)-catalyzed cross-coupling with aryl halides.
S. Ma, Q. He, X. Zhang, J. Org. Chem., 2005, 70, 3336-3338.
A mild, stereospecific cross-coupling of unsymmetrical 1,4-bissilyl-1,3-butadienes has been developed. A selective cross-coupling under mildly basic conditions afforded 4-aryl-1,3-dienylsilanes in excellent yield for a wide range coupling partners. The subsequent cross-coupling of the 4-aryl-1,3-dienylsilanes could be effected cleanly by the action of TBAF with electron-rich or electron-poor halides.
S. E. Denmark, S. A. Tymonko, J. Am. Chem. Soc., 2005, 127, 8004-8005.
The rhodium-catalyzed reaction of aryl boronic acids with internal alkynes and acrylates in water gives the domino coupling products. The reaction demonstrates that water offers the possibility to discover novel transformations.
T. Kurahashi, H. Shinokubo, A. Osuka, Angew. Chem. Int. Ed., 2006, 45, 6336-6338.
Privileged allylic amine structures can be constructed in a regioselective, stereoselective, and diversity-oriented manner by a novel palladium-catalyzed four-component assembly based on allenylboronate platform. A short synthesis of rolipram is also demonstrated.
K. Tonogaki, K. Itami, J.-I. Yoshida, J. Am. Chem. Soc., 2006, 128, 1464-1465.
Homoallylic α-amino esters and amines were prepared via a Pd(II)-catalyzed coupling of 1,2-nonadiene and boronic acids with ethyl iminoacetate or aliphatic, aromatic, and heteroaromatic imines.
C. D. Hopkins, H. C. Malinakova, Org. Lett., 2006, 8, 5971-5974.
A mild, Pd/C-catalyzed Suzuki-Miyaura coupling of 2-iodocycloenones with arylboronic acids is described. Notably, the procedure features inexpensive reagents, reactions under air, and solvents with low toxicity. In addition, the Pd/C could be reused at least five times.
F.-X. Felpin, J. Org. Chem., 2005, 70, 8575-8578.
Monofluorovinyl tosylate is practical vinyl fluoride building block to couple with various arylboronic acids in the presence of a palladium catalyst. A high stereoselectivity in the synthesis of 2-aryl-1-fluoroethene derivatives was achieved. This approach is also applicable to the synthesis of 2,2-diaryl-1-fluoroethenes in good yields.
H. Zhang, C.-B. Zhou, Q.-Y. Chen, J.-C. Xiao, R. Hong, Org. Lett., 2011, 13, 560-563.
A scalable, direct functionalization of various quinones with several boronic acids proceeds readily at room temperature in an open flask using catalytic silver(I) nitrate in the presence of a persulfate co-oxidant. The scope with respect to quinones is broad, with a variety of alkyl- and arylboronic acids undergoing efficient cross-coupling.
Y. Fujiwara, V. Domingo, I. B. Seiple, R. Gianatassio, M. Del Bel, P. P. S. Baran, J. Am. Chem. Soc., 2011, 133, 3292-3295.