6230-62-2Relevant articles and documents
Catalyst-Controlled Chemodivergent Reactions of 2-Pyrrolyl-α-diazo-β-ketoesters and Enol Ethers: Synthesis of 1,2-Dihydrofuran Acetals and Highly Substituted Indoles
France, Stefan,Guerra Faura, Gabriel,Nguyen, Tena
supporting information, p. 10088 - 10104 (2021/07/31)
A catalyst-controlled, chemodivergent reaction of pyrrolyl-α-diazo-β-ketoesters with enol ethers is reported. While Cu(II) catalysts selectively promoted a [3 + 2] cycloaddition to provide pyrrolyl-substituted 2,3-dihydrofuran (DHF) acetals, dimeric Rh(II) catalysts afforded 6-hydroxyindole-7-carboxylates via an unreported [4 + 2] benzannulation. The choice of enol ether proved to be crucial in determining both regioselectivity and yield of the respective products (up to 91% yield for Cu(II) and 82% for Rh(II) catalysis). Furthermore, the DHF acetals were shown to serve as precursors to 7-hydroxyindole-6-carboxylates (isomeric to the indoles formed from Rh) and highly substituted furans in the presence of Lewis acids. Thus, from a common pyrrolyl-α-diazo-β-ketoester, up to three unique heterocyclic scaffolds can be achieved based on catalyst selection.
A facile solid-phase synthesis of vinyl ethers using a selenium traceless linker
Liu, Xiao-Ling,Sheng, Shou-Ri,Wang, Qiu-Ying,Sun, Wu-Kang,Xin, Qin,Ao, Hong-Yu
, p. 118 - 120 (2007/10/03)
A simple, efficient and environmentally friendly procedure for the solid-phase synthesis of vinyl ethers in good yields and purities by reaction of polystyrene-supported 2-hydroxyalkyl selenide with primary or secondary organic halides and subsequent oxid
Ionic liquid-promoted, highly regioselective Heck arylation of electron-rich olefins by aryl halides
Mo, Jun,Xu, Lijin,Xiao, Jianliang
, p. 751 - 760 (2007/10/03)
Palladium-catalyzed regioselective Heck arylation of the electron-rich olefins, vinyl ethers 1a-d, enamides 1e-g, and allyltrimethylsilane 1h, has been accomplished in imidazolium ionic liquids with a wide range of aryl bromides and iodides instead of the commonly used, but commercially unavailable and expensive, aryl triflates. The reaction proceeded with high efficiency and remarkable regioselectivity without the need for costly or toxic halide scavengers, leading exclusively to substitution by aryl groups of diverse electronic and steric properties at the olefinic carbon α to the heteroatom of 1a-g and β to the heteroatom of 1h. In contrast, the arylation reaction in molecular solvents led to mixtures of regioisomers under similar conditions. Several lines of evidence point to the unique regiocontrol stemming from the ionic environment provided by the ionic liquid that alters the reaction pathway. The chemistry provides a simple, effective method for preparing branched, arylated olefins and contributes to the extension of Heck reaction to a wider range of substrates.
