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
Aryl Boronic Acid Catalysed Dehydrative Substitution of Benzylic Alcohols for C−O Bond Formation
作者:Susana Estopiñá‐Durán、Liam J. Donnelly、Euan B. Mclean、Bryony M. Hockin、Alexandra M. Z. Slawin、James E. Taylor
DOI:10.1002/chem.201806057
日期:2019.3.12
substitution of benzylicalcohols with a second alcohol to form new C−Obonds. This method has been applied to the intermolecular substitution of benzylicalcohols to form symmetrical ethers, intramolecular cyclisations of diols to form aryl‐substituted tetrahydrofuran and tetrahydropyran derivatives, and intermolecular crossed‐etherification reactions between two different alcohols. Mechanistic control
A nitrite-catalyzed ring contraction reaction of substituted tetrahydrofurans by oxidation of bromide under aerobic conditions as a dehydrogenative dual functionalization was developed to provide 2-acyltetrahydrofurans in good yields. On the other hand, the oxidation reaction of 1-substituted isochromans occurred via the bromohydroxylation to give 1-(dibromoalkyl)-1-hydroxyisochromans in high yields