Synthesis of substituted 1,3-diynes
A cross-coupling of terminal alkynes with 1-bromoalkynes in the presence of copper(I) iodide and tris(o-tolyl)phosphine enables the synthesis of unsymmetrical buta-1,3-diynes in good yields under simple and mild reaction conditions. The scope and limitations of the cross-coupling reaction were investigated.
S. Wang, L. Yu, P. Li, L. Meng, L. Wang, Synthesis, 2011, 1541-1546.
A new Pd-catalyzed protocol realized the cross-coupling of a broad scope of terminal alkynes and haloalkynes in good to excellent yields with high selectivities and without homocoupling using a phosphine-olefin ligand. Electron-rich alkynes, which are normally difficult substrates in Glaser couplings, could be employed as either nucleophiles or electrophiles.
W. Shi, Y. Luo, X. Luo, L. Chao, H. Zhang, J. Wang, A. Lei, J. Am. Chem. Soc., 2008, 130, 14713-14720.
Gold-catalyzed oxidative cross-coupling of alkynes to unsymmetrical diynes has been achieved in the presence of 1,10-Phen as ligand and PhI(OAc)2 as oxidant giving the desired cross-coupled conjugated diynes in excellent heteroselectivity (>10:1), in good to excellent yields, and with large substrate tolerability.
H. Peng, Y. Xi, N. Ronaghi, B. Dong, N. G. Akhmedov, X. Shi, J. Am. Chem. Soc., 2014, 136, 13174-13177.
An efficient cross-coupling of alkynyl bromides and boronates to produce unsymmetric 1,3-diynes is catalyzed by CuFe2O4 nanoparticles in dimethyl carbonate. The protocol also enables a coupling of alkynyl bromides and alkenyl boronic acids to provide conjugated 1,3-enynes. The catalyst was easily separated by an external magnet and recycled 10 times.
S. Ahammed, D. Kundu, B. C. Ranu, J. Org. Chem., 2014, 79, 7391-7398.
An efficient Sonogashira coupling of terminal alkynes and styrenyl bromides is catalyzed by hydroxyapatite-supported copper(I). Trans-styrenyl bromides produce trans-enyne products, whereas cis-styrenyl bromides lead to unsymmetric 1,3-diynes by the cross coupling of terminal alkyne and the alkyne generated from the cis-styrenyl bromide.
D. Saha, T. Chatterjee, M. Mukherjee, B. C. Ranu, J. Org. Chem., 2012, 77, 9379-9383.
In a copper-catalyzed decarboxylative coupling reaction, a broad range of aryl, alkenyl, alkynyl, and alkyl substituted 1,1-dibromo-1-alkenes react smoothly with aryl and alkyl substituted potassium propiolates to produce unsymmetrical 1,3-diynes and 1,3,5-triynes with high selectivity and good functional group compatibility.
Z. Huang, R. Shang, Z.-R. Zhang, X.-D. Tan, X. Xiao, Y. Fu, J. Org. Chem., 2013, 78, 4551-4557.
In the presence of palladium(II) acetate and copper(I) iodide, unsymmetrical buta-1,3-diynes were selectively obtained from the reaction of (E)-1,2-diiodoalkenes with terminal alkynes in moderate to good yields at room temperature. Using the same conditions, the coupling of 2-ethynylphenol with (E)-1,2-diiodoalkenes followed by a cyclization at 100°C gives ethynylbenzofurans.
Y. Liang, L.-M. Tao, Y.-H. Zhang, J.-H. Li, Synthesis, 2008, 3988-3994.
A Rh(I)-catalyzed C-C activation of diynones enables the synthesis of symmetrical and unsymmetrical conjugated diynes through decarbonylation. This C-C cleavage strategy takes advantage of the innate reactivity of conjugated ynones without relying on any ring strain or auxiliary directing group.
A. Dermenci, R. E. Whittaker, G. Dong, Org. Lett., 2013, 15, 2242-2245.
A carbenoid Fritsch-Buttenberg-Wiechell (FBW) rearrangement of a substituted dibromoolefinic precursor is used to generate a lithium acetylide, and subsequent trapping with carbon-based electrophiles provides a wide range of di- and triynes. The lithium acetylide formed from the FBW reaction can also undergo transmetalation to provide zinc, copper, tin, or platinum acetylides.
T. Luu, Y. Morisaki, N. Cunningham, R. R. Tykwinski, J. Org. Chem., 2007, 72, 9622-9629.
Nonafluorobutanesulfonyl azide is a highly efficient reagent for an extremely fast copper-catalyzed coupling of terminal alkynes to give symmetrical and unsymmetrical 1,3-diynes in good to excellent yields and with good functional group compatibility. In addition, nonafluorobutanesulfonyl azide is a superior and safe alternative to other electrophilic azide reagents in use today.
J. R. Suárez, D. Collado-Sanz, D. J. Cárdenas, J. L. Chiara, J. Org. Chem., 2015, 80, 1098-1106.
A facile and environmentally friendly synthetic method for a variety of symmetrical 1,3-diyne derivatives is based on a Pd/C-CuI-catalyzed homocoupling reaction of terminal alkynes. The reaction was efficiently catalyzed by an extremely low loading of Pd/C and CuI in the presence of molecular oxygen as the oxidant without any phosphine ligands and bases.
T. Kurita, M. Abe, T. Maegawa, Y. Monguchi, H. Sajiki, Synlett, 2007, 2521-2524.
A palladium-catalyzed dimerization of terminal acetylenes with iodosylbenzene as oxidant allowed the preparation of various diynes in good yields in a short period of time at room temperature.
J. Yan, F. Lin, Z. Yang, Synthesis, 2007, 1301-1303.