Additions of singlet oxygen to alkoxy-substituted butadienes. An unexpectedly large s-cis/s-trans ratio in an (E,Z)-diene or a kinetic anomeric effect?
and practical route for the preparation of highly substituted fluorenones and analogues via solvent-free ruthenium trichloride mediated [2 + 2 + 2] cycloaddition of α,ω-diynes and alkynes has been developed. This green chemistry approach involves a solventless and atom-economical catalytic process to generate densely functionalized fluorenones and related derivatives of high synthetic utility.
Palladium-catalyzed desymmetric [2+2+2] cycloaddition of 1,6-enyne and alkyne
作者:Wei-Cheng Zhao、Xin Wang、Juhua Feng、Ping Tian、Zhi-Tao He
DOI:10.1016/j.tet.2020.131862
日期:2021.1
desymmetric [2+2+2] cycloaddition reaction of alkyne-tethered cyclohexadienone and internal alkyne is established. Widely existing fused tricyclic hydronaphthofuran and hydronaphthopyrrole frameworks are prepared diastereoselectively in moderate to excellent yields. One-step aromatization process provides a new and facile access to important benzene-containing tricycles from above cycloaddition products
Cyclotrimerisation catalytique d'alcynes par des complexes du nickel formés “in situ”
作者:P. Alphonse、F. Moyen、P. Mazerolles
DOI:10.1016/0022-328x(88)80249-3
日期:1988.5
Catalytic cyclotrimerization of acetylenic compounds by transient complexes formed in the reduction of nickelhalides by magnesium, occurs with many alkynes; however, this cyclization is hindered when bulky groups are close neighbors of the triple bond or when acceptor groups are in the α position with respect to the unsaturated carbon. On the other hand, the yield of trimer increases to become quantitative
A Simple and Powerful tert-Butylation of Carboxylic Acids and Alcohols
作者:Kosuke Namba、Chie Ogasa、Kimika Kayano
DOI:10.1055/a-2161-9689
日期:2024.1
A simple and safe tert-butylation reaction was developed. Treatment of various free amino acids with 1.1 equivalents of bis(trifluoromethanesulfonyl)imide in tert-butyl acetate directly afforded tert-butyl esters with free amino groups quickly and in good yields. In addition, various carboxylicacids and alcohols without amino groups were converted into tert-butyl esters and ethers, respectively, in