compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones
C(
<i>sp</i>
<sup>3</sup>
)−C(
<i>sp</i>
<sup>3</sup>
) Cross‐Coupling of Alkyl Bromides and Ethers Mediated by Metal and Visible Light Photoredox Catalysis
作者:Marilia S. Santos、Arlene G. Corrêa、Márcio W. Paixão、Burkhard König
DOI:10.1002/adsc.202000167
日期:2020.6.15
We report a C(sp3)−C(sp3) cross‐coupling of alkyl bromides and alkyl chlorides with ethers by dual photoredox‐nickel catalysis. The catalytic system comprises of the organic photocatalyst 1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene (4‐CzIPN) and bench stable nickel (II) acetylacetonate in the presence of visible‐light, providing the coupling products in up to 92% yield. Preliminary mechanistic
Nickel Complex Catalyzed Efficient Activation of sp3 and sp2 C–H Bonds for Alkylation and Arylation of Oxygen Containing Heterocyclic Molecules
作者:Yashraj Gartia、Punnamchandar Ramidi、Darin E. Jones、Sharon Pulla、Anindya Ghosh
DOI:10.1007/s10562-013-1170-8
日期:2014.3
A nickel(II) complex (1) of N,N′-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamido (L) ligand was examined for catalytic coupling of Grignardreagents with the C–H bond of oxygen containing heterocyclic compounds such as tetrahydrofuran and furan. The nickel(II) complex showed excellent activity in catalyzing C–H activation and further coupling with various Grignardreagents. The effective activation
New method for C–H arylation/alkylation at α-position of cyclic aliphatic ethers by iron-oxide mediated reaction
作者:Parvinder Pal Singh、Satish Gudup、Hariprasad Aruri、Umed Singh、Srinivas Ambala、Mahipal Yadav、Sanghapal D. Sawant、Ram A. Vishwakarma
DOI:10.1039/c1ob06660a
日期:——
We report a new and efficient iron oxide catalyzed cross-coupling reaction between organometallic species such as alkyl/arylmagnesium halides or organolithium species and α-hydrogen bearing cyclic unbranched and branched aliphatic ethers via activation of C(sp3)–H. In the presence of 1 mol% of iron oxide, five and six membered unbranched cyclic ethers such as tetrahydrofuran and tetrahydropyran gave
Cyclic ethers have been effectively synthesized via the intramolecular cyclization of diols using trimethyl phosphate and NaH. The present cyclization could proceed at room temperature to produce 5–7 membered cyclic ethers in good to excellent yields. Substrates possessing a chiral secondary hydroxy group were transformed into the corresponding chiral cyclic ethers along with the retention of their