Categories: C-N Bond Formation >
Synthesis of sulfonamides
Using 0.5 mol % [Ru(p-cymene)Cl2]2 with the bidentate phosphines dppf or DPEphos as the catalyst, primary amines have been converted into secondary amines, and secondary amines into tertiary amines. N-Heterocyclization reactions of primary amines have been achieved, as well as alkylation reactions of primary sulfonamides.
M. H. S. A. Hamid, C. L. Allen, G. W. Lamb, A. C. Maxwell, H. C. Maytum, A. J. A. Watson, J. M. J. Williams, J. Am. Chem. Soc., 2009, 131, 1766-1774.
A catalytic amount of manganese dioxide and solvent-free conditions under air enabled a practical and efficient N-alkylation method for a variety of sulfonamides and amines using alcohols as green alkylating reagents.
X. Yu, C. Liu, L. Jiang, Q. Xu, Org. Lett., 2011, 13, 6184-6187.
Microwave heating enables a Borrowing Hydrogen strategy to form C-N bonds from alcohols and amines, removes the need for solvent and reduces the reaction times, while the results are comparable with those using thermal heating.
A. J. A. Watson, A. C. Maxwell, J. M. J. Williams, J. Org. Chem., 2011, 76, 2328-2331.
A convenient, general, and high yielding Pd-catalyzed cross-coupling of methanesulfonamide with aryl bromides and chlorides eliminates concern over genotoxic impurities that can arise when an aniline is reacted with methanesulfonyl chloride. The application of this method to the synthesis of dofetilide is also reported.
B. R. Rosen, J. C. Ruble, T. J. Beauchamp, A. Navarro, Org. Lett., 2011, 13, 2564-2567.
A biaryl phosphine ligand, t-BuXPhos and K3PO4 in tert-amyl alcohol was found to be the optimal base-solvent combination for a Pd-catalyzed sulfonamidation of aryl nonafluorobutanesulfonates. The reaction conditions were tolerant of various functional groups. The only identified limitation of this methodology is the inability of 2,6-disubstituted aryl nonaflates to efficiently participate in the reaction.
S. Shekhar, T. B. Dunn, B. J. Kotecki, D. K. Montavon, S. C. Cullen, J. Org. Chem., 2011, 76, 4552-4553.
The arylation of N-H and O-H containing compounds at room temperature with phenylboronic acids is promoted in the presence of cupric acetate and a tertiary amine. Substrates include phenols, amines, anilines, amides, imides, ureas, carbamates, and sulfonamides.
D. M. T. Chan, K. L. Monaco, R.-P. Wang, M. P. Winteres, Tetrahedron Lett., 1998, 39, 2933-2936.
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.
A range of enol triflates can be coupled with amides, carbamates, and sulfonamides using palladium catalysis. This method allows the synthesis of enamides, which may not be readily available by other means.
D. J. Wallace, D. J. Klauber, C.-Y. Chen, R. P. Volante, Org. Lett., 2003, 5, 4749-4752.
Nucleophilic addition of sulfonamides to 1-bromo-1-alkynes provided (Z)-N-(1-bromo-1-alken-2-yl)-p-toluenesulfonamides in good yield and in a highly regio- and stereoselective manner. A subsequent reaction in the presence of a palladium catalyst under Heck conditions afforded substituted pyrroles in good yield.
M. Yamagishi, K. Nishigai, T. Hata, H. Urabe, Org. Lett., 2011, 13, 4873-4875.
Benzylic hydrocarbons are selectively converted to the corresponding sulfonamides by the [Cu(CH3CN)4]PF6-catalyzed reaction with anhydrous TolSO2NNaCl (chloramine-T). Under the same conditions, representative ethers and olefins are also amidated.
R. Bhuyan, K. M. Nicholas, Org. Lett., 2007, 9, 3957-3959.
A copper-catalyzed amidation of allylic and benzylic C-H is applicable to the coupling of a diverse set of hydrocarbon species with aryl, heteroaryl, and alkyl sulfonamides and is tolerant of a variety of functional groups.
G. Pelletier, D. A. Powell, Org. Lett., 2006, 8, 6031-6034.
A single Cu(II) catalyst couples a diverse range of nitrogen sources with various alkynes and aldehydes without the addition of ligand or base. Copper-catalyzed alkynylation involving p-toluenesulfonamide provides high yields of N-Ts-protected propargylamines. The superior activity of copper(II) triflate also allows this three-component alkynylation to incorporate a ketone.
C. E. Meyet, C. J. Pierce, C. H. Larsen, Org. Lett., 2012, 14, 964-967.
The use of PhI=NTs/PhI=NNs as the nitrogen source in the presence of inexpensive iron(II) chloride + pyridine as the in situ formed precatalyst enables amidation of aldehydes under mild conditions at room temperature or microwave assisted conditions. The protocol is operationally straightforward and accomplished in good product yields and with complete chemoselectivity.
T. M. U. Ton, C. Tejo, S. Tania, J. W. W. Chang, P. W. H. Chan, J. Org. Chem., 2011, 76, 4894-4904.
A gold(I)-catalyzed decarboxylative amination of allylic N-tosylcarbamates via base-induced aza-Claisen rearrangement in H2O allows the synthesis of substituted N-tosyl allylic amines in good yield, regioselectivity, and stereoselectivity. This transformation represents an efficient and environmentally benign protocol for the synthesis of N-tosyl allylic amines.
D. Xing, D. Yang, Org. Lett., 2010, 12, 1068-1071.
An economic and practical transformation from secondary alkyl-substituted propargyl acetates to a variety of nucleophilic substitution products is catalyzed by inexpensive InCl3. High yields and excellent chemoselectivity were obtained. Five-, six-, and seven-membered propargyl cycloethers were also successfully constructed.
M. Lin, L. Hao, X.-t. Liu, Q.-z. Chen, F. Wu, P. Yan, S.-x. Xu, X.-l. Chen, J.-j. Wen, Z.-p. Zhan, Synlett, 2011, 665-670.
An efficient amidation reaction of saturated C-H bonds catalyzed by a unique disilver(I) complex is reported. The reaction is stereospecific and practical for the construction of amine-containing molecules.
Y. Cui, C. He, Angew. Chem. Int. Ed., 2004, 43, 4210-4212.
A highly efficient hydroamination of sulfonamides, carboxamides, and carbamates with unactivated olefins is catalyzed by an inexpensive zirconium salt under mild reaction conditions. The reactions gave good to excellent yields of the Markovnikov products.
L. Yang, L.-W. Xu, W. Zhou, Y.-H. Gao, W. Sun, C.-G. Xia, Synlett, 2009, 1167-1171.
A simple addition of phenols, carboxylic acids, and protected amines to olefins can be catalyzed by triflic acid. A low concentration of triflic acid and control of the reaction temperature help to tolerate functional groups, such as methoxyl substitution on aromatics.
Z. Li, J. Zhang, C. Brouwer, C.-G. Yang, N. W. Reich, C. He, Org. Lett., 2006, 8, 4175-4178.
Addition of sulfonamides to alkenes and conjugated dienes can be carried out using a low catalytic amount of (triphenyl phosphite)gold(I) chloride and silver triflate under thermal or microwave conditions and at r.t. in the case of dienes. Terminal alkenes undergo regioselective hydroamination at the internal carbon atom and dienes at the less substituted double bond.
X. Giner, C. Nájera, Org. Lett., 2008, 10, 2919-2922.
A combined amino- and N-heterocyclic carbene (NHC)-catalyzed one-pot reaction sequence using commercially available catalysts at low catalyst loadings gives β-hydroxy and β-amino esters in high yield and excellent enantiopurity. The generation of quaternary stereocenters and application in gram-scale synthesis were also realized, with no requirements of inert or anhydrous reaction conditions.
H. Jiang, B. Gschwend, Ł. Albrecht, K. A. Jřrgensen, Org. Lett., 2010, 12, 5052-5055.
The use of iodosobenzene (PhIO) as oxidant and p-toluenesulfonamide (TsNH2) as aminating reagent in the presence of a catalytic amount of perchlorate zinc hexahydrate enables a direct α-amination of β-dicarbonyl compounds. The reaction proceeds quickly at rt to provide the corresponding α-N-tosylamido β-dicarbonyl compounds very good yields.
J. Yu, S.-S. Liu, J. Cui, X.-S. Hou, C. Zhang, Org. Lett., 2012, 14, 832-835.
In copper-catalyzed direct N-alkynylation, the use of pure and anhydrous K3PO4 provides higher ynamide yields in comparison to samples contaminated with hydrates (K3PO4 · 1.5 H2O and K3PO4 · 7 H2O). With high quality K3PO4, a number of ynamides were synthesized in good yields. In addition, ynamides can undergo regioselective hydroamination with carbamates.
K. Dooleweerd, H. Birkedal, T. Ruhland, T. Skrydstrup, J. Org. Chem., 2008, 73, 9447-9450.
A facile route to ynamides in high yields was achieved through an iron-catalyzed C-N coupling reaction of amides with alkynyl bromides in the presence of 20 mol % of N,N′-dimethylethane-1,2-diamine (DMEDA).
B. Yao, Z. Liang, T. Niu, Y. Zhang, J. Org. Chem., 2009, 74, 4630-4633.
A new procedure for aminobromination of olefins gives vicinal bromoamine derivatives in high yields using Cu, Mn, or V catalysts with p-toluenesulfonamide as nitrogen source and N-bromosuccinimide (NBS) as bromine source. Excellent regio- and stereoselectivity is shown for different olefinic substrates as well as transition metal catalysts.
V. V. Thakur, S. K. Talluri, A. Sudalai, Org. Lett., 2003, 5, 861-864.
A convenient and efficient iron-catalyzed aminobromination of alkenes has been developed using inexpensive FeCl2 as the catalyst, amides/sulfonamides and NBS as the nitrogen and bromine sources, respectively, under mild conditions.
Z. Wang, Y. Zhang, H. Fu, Y. Jiang, Y. Zhao, Synlett, 2008, 2667-2668.
A Rh(II)-catalyzed oxidative coupling of aldehydes and sulfonamides provides N-sulfonylcarboxamides in one step. Various sulfonamides were found to react with aromatic and aliphatic aldehydes to afford the desired products in very good yields.
J. Chan, K. D. Baucom, J. A. Murry, J. Am. Chem. Soc., 2007, 129, 14106-14107.