New method for the synthesis of α-substituted tetrahydrofuran-2-methanols through diastereoselective addition of THF to aldehydes mediated by Et3B in the presence of air
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
A new oxygen-centered radicalcyclization onto silylenolethers has been developed and utilized for the synthesis of versatile siloxy-substituted tetrahydrofurans. The reactions display excellent chemoselectivity for cyclization onto the electron-rich silylenolether when competing terminal alkene cyclization, 1,5-hydrogen abstraction, and beta-fragmentation pathways are present. The increased chemoselectivity
Combined Photoredox and Lewis Acid Catalyzed α-Hydroxyalkylation of Cyclic Ethers with Aromatic Ketones
作者:Melissa Reckenthäler、Jörg-M. Neudörfl、Elif Zorlu、Axel G. Griesbeck
DOI:10.1021/acs.joc.6b01085
日期:2016.8.19
The photochemically induced coupling of aromatic ketones with cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane was studied. Direct photolysis of the substrates with UV-A light centered at 350 nm does not lead to photoinduced hydrogen transfer whereas the addition of a mixture of the Lewis acid catalysts Ti(OiPr)4 and BF3 enables the formation of the hydroxyalkylation products
研究了芳族酮与环醚(如四氢呋喃,四氢吡喃和1,4-二恶烷)的光化学诱导偶联。用居中于350 nm的UV-A光直接对底物进行光解不会导致光诱导的氢转移,而添加路易斯酸催化剂Ti(O i Pr)4和BF 3的混合物能够形成羟烷基化产物。
Diastereoselectivite dans la reaction des organomagnesiens sur le tetrahydrofurfural et son gem-diacetate en presence de HMPT. Acces aux diols-1,2 erythro
作者:R. Amouroux、S. Ejjiyar、M. Chastrette
DOI:10.1016/s0040-4039(86)80041-7
日期:1986.1
Hydroxyalkylation of α-C−H Bonds of Tetrahydrofuran with Aldehydes in the Presence of Triethylborane and <i>tert</i>-Butyl Hydroperoxide
The alpha-hydroxyalkylation of tetrahydrofuran with aldehydes via radical C-H abstraction was conducted using triethylborane in the presence of tert-butyl hydroperoxide. This study presents a rare instance of direct intermolecular radical addition of unactivated cyclic ether to aldehydes.