Synthesis of 2-(arylthio)benzoates by [3+3] cyclocondensations of 3-arylthio-1-silyloxy-1,3-butadienes with 3-oxo-orthoesters, 1,1,3,3-tetramethoxypropane and 1,1-bis(methylthio)-1-en-3-ones

A variety of 2-arylthio-4-methoxybenzoates are regioselectively prepared by TiCl₄-mediated [3+3] cyclocondensations of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 3-oxo-orthoesters. Unsubstituted 2-(arylthio)benzoates were prepared by Me₃SiOTf-catalyzed cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1,3,3-tetramethoxypropane. The TiCl₄-mediated cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1-bis(methylthio)-1-en-3-ones results in regioselective formation of 2-arylthio-6-(methylthio)benzoates.     

Regioselective synthesis of 2-acetyl- and 2-alkoxycarbonyl-3-(trifluoromethyl)phenols by [3+3] cyclization of 1,3-bis-silyl enol ethers with 4-ethoxy- and 4-silyloxy-1,1,1-trifluoroalk-3-en-2-ones

2-Acetyl- and 2-alkoxycarbonyl-3-(trifluoromethyl)phenols were prepared by [3+3] cyclization of 1,3-bis-silyl enol ethers with 4-ethoxy- and 4-silyloxy-1,1,1-trifluoroalk-3-en-2-ones.     

Highly efficient Pd(acac)2/TFA catalyzed head-to-tail dimerization of vinylarenes at room temperature

Pd(acac)₂ catalyzed dimerization of vinylarenes to form dimers under mild condition with excellent yields and stereoselectivities. In particular, the use of TFA highly promoted the activity and selectivity of the dimerization. The studies on mechanism for the reaction displayed clearly that the dimerization of styrenes is 100% atom economic reaction.     

Synthesis of of sterically encumbered biaryls based on a ‘copper(I)-catalyzed arylation/[3+3] cyclocondensation’ strategy

Sterically encumbered biaryls are prepared in two steps by combination of the CuI-proline-catalyzed arylation of acetylacetone with formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes. In addition, the synthesis of 4,6- and 5,6-diarylsalicylates based on [3+3] cyclizations is reported.     

Catalyst-free Friedel-Crafts reaction of 1-(N-acylamino)alkyltriarylphosphonium salts with electron-rich arenes

Friedel-Crafts reaction of 1-(N-acylamino)alkyltriarylphosphonium salts with arenes or heteroarenes without the need for any catalyst provided access to a wide range of biologically interesting N-(1-arylalkyl)amides or 1-arylalkylphosphonium salts which can be of great interest in the chemistry of ylides and phosphonium ionic liquids. Depending on reaction conditions and substrate structure, the reaction can be conducted selectively with high yields toward each of the above-mentioned products. Mechanistic aspects of the above transformations were also considered.     

Bifunctional Silyl Triflates in Synthesis,Part 1: Synthesis and Characterization of Novel Alkane-α,ω-diyl-bis(silyl triflates)

We report the preparation of two bifunctional silyl triflates, 1,1,4,4-tetramethyl-1,4-disila-1,4-butanediyl-bis(trifluoromethanesulfonate) and 1,1,5,5-tetramethyl-1,5-disila-1,5-pentanediyl-bis(trifluoromethanesulfonate). Detailed synthetic procedures and characterization data are described.     

Synthesis of functionalized 2-(arylthio)benzoates by formal [3+3] cyclizations of 3-arylthio-1-silyloxy-1,3-butadienes with 3-silyloxy-2-en-1-ones and 1,3-diacylcyclopropanes

Functionalized 2-(arylthio)benzoates are prepared by formal [3+3] cyclizations of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 3-silyloxy-2-en-1-ones and 1,1-diacylcyclopropanes.     

Synthesis and reactions of the first fluoroalkylated 1,3-bis(trimethylsilyloxy)-1,3-butadienes

The first fluoroalkylated 1,3-bis(silyloxy)-1,3-butadienes have been prepared. Their reaction with oxalyl chloride provides a convenient approach to fluoroalkylated γ-alkylidenebutenolides.     

Synthesis and Crystal Structures of New Palladium(II)—Gallium(III) Complexes with Bridging Halogenide Ligands

The reaction of palladium(II) bromide or palladium(II) iodide with the respective gallium(III) halogenide in the presence of aromatic solvents leads to the formation of palladium(II) tetrabromo— and tetraiodogallate. The compounds are isostructural {monoclinic, C2/m, Pd[GaBr₄]₂: a = 1267(2), b = 808(1), c = 722(1) pm, β = 94.5(1)°; Pd[GaI₄]₂: a = 1363(1), b = 849.9(4), c = 756.6(7) pm, β = 95.38(3)°}. The structures contain mononuclear complexes Pd[GaX₄]₂, where X^— = Br^— ( 1 ), I^— ( 2 ). The crystal structures of 1 and 2 were determined by single‐crystal X‐ray diffraction. Crystals of both compounds turned out to be similarly twinned.