Au<sub>2</sub>O<sub>3</sub> as a Stable and Efficient Catalyst for the Selective Cycloisomerization of γ-Acetylenic Carboxylic Acids to γ-Alkylidene-γ-Butyrolactones
The high potential of commercially available Au2O3 as a catalyst in the cyclization of alkynes bearing carboxylic acids to the corresponding γ-alkylidene-γ-butyrolactones through a general, efficient and easy procedure is presented. The reaction shows a high degree of chemo-, regio-, and stereoselectivity. The 5-exo mode of cyclization and anti auration are a general trend for the Au2O3 catalyst.
Cyclisation of acetylenecarboxylic acid. Synthesis of γ-methylenebutyrolactones
作者:Makoto Yamamoto
DOI:10.1039/p19810000582
日期:——
Various γ-exo-methylenebutyrolactones have been synthesized in excellent yield by the cyclisation of acetylenecarboxylicacids in the presence of a catalytic amount of mercury(II) oxide. Cyclisation of terminal acetylene compounds[e.g.(1a)–(1e)]proceeded regioselectively to give γ-exo-methylenebutyrolactones as the sole product. Disubstituted acetylenes [(1f)–(1i)] also gave the (Z)-configurational
Palladium(II) catalyzed cyclization of alkynoic acids
作者:Claude Lambert、Kiitiro Utimoto、Hitosi Nozaki
DOI:10.1016/s0040-4039(01)81594-x
日期:——
Under the catalytic action of palladium(II) in the presence of triethylamine, 3-, 4-, and 5-alkynoic acids afford 3-buten-4-olides, 4-penten-4-olides, and 5-hexen-5-olide, respectively, in good to excellent yields.
Gold imidazolium-based ionic liquids, efficient catalysts for cycloisomerization of γ-acetylenic carboxylic acids
作者:Florentina Neaţu、Vasile I. Pârvulescu、Véronique Michelet、Jean-Pierre Gênet、Alexandre Goguet、Christopher Hardacre
DOI:10.1039/b812580e
日期:——
Ionic liquid stabilized gold(III) chloride is shown to be a very active catalyst in the cyclization of sterically hindered and unhindered acetylenic carboxylic acid substrates even in the absence of a base.
Novel Pd heterogeneous catalysts for cycloisomerisation of acetylenic carboxylic acids
作者:Florentina Neaţu、Loredana Proteşescu、Mihaela Florea、Vasile I. Pârvulescu、Cristian M. Teodorescu、Nicoleta Apostol、Patrick Y. Toullec、Véronique Michelet
DOI:10.1039/c0gc00258e
日期:——
The Pd-TPPTS complex (TPPTS - trisodium salt of 3,3′,3′′-phosphanetriyl benzenesulfonic acid) and PdCl42− salt heterogenised onto Zn2AlNO3 layered double hydroxide (LDH) using an ion-exchange procedure, have been shown to be efficient green catalysts in the cycloisomerisation reaction of acetylenic carboxylic acids to the corresponding 5-membered heterocycles.