Ruthenium-Catalyzed Transfer Oxygenative Cyclization of α,ω-Diynes: Unprecedented [2 + 2 + 1] Route to Bicyclic Furans via Ruthenacyclopentatriene
摘要:
A novel oxygen-atom-transfer process enables the catalytic [2 + 2 + 1] synthesis of bicyclic furans from alpha,omega-diynes with DMSO. [CpRu(AN)(3)]PF6 catalyzed the transfer oxygenative cyclization of diynes with aryl terminal groups, while those of diynes with alkyl terminal groups were effectively promoted by the corresponding Cp* complex. A mechanism for bicyclic furan formation via a ruthenacyclopentatriene was proposed on the basis of both experimental and theoretical studies.
successfully applied to the synthesis of terpyridine and quinquepyridine. This chemistry was extended to a new and efficient synthesis of oligoheteroarenes. Five aromatic or heteroaromatic rings were connected in a single operation. [Ir(cod)Cl](2)/chiral diphosphine catalyst can be applied to enantioselective synthesis. Kinetic resolution of the racemic secondary benzyl nitrile catalyzed by [Ir(cod)Cl](2)/SEGPHOS
[Ir(cod)Cl](2)/DPPF 或 BINAP 有效地催化 α,ω-二炔与腈的环加成反应生成吡啶。该反应可以适应范围很广的腈。脂肪族和芳香族腈均与 α,ω-二炔顺利反应生成吡啶。十当量的未活化脂族腈足以得到高产率的产物。带有缩醛或氨基部分的脂肪腈可用于该反应。实现了带有两个不同内部炔烃部分的不对称二炔的高度区域选择性环加成。考虑到环戊二烯中α-位的不同反应性,可以合理地解释观察到的区域选择性。区域选择性环加成成功地应用于三联吡啶和喹啉吡啶的合成。这种化学反应扩展到一种新的、有效的低聚杂芳烃合成方法。在一次操作中连接了五个芳环或杂芳环。[Ir(cod)Cl](2)/手性二膦催化剂可用于对映选择性合成。[Ir(cod)Cl](2)/SEGPHOS 催化的外消旋仲苄腈的动力学拆分得到了 80% ee 的中心碳手性吡啶。基于B3LYP水平的密度泛函计算分析了机理。
Palladium(0)-Catalyzed Intermolecular Carbocyclization of (1,<i>n</i>)-Diynes and Bromophenols: An Efficient Route to Tricyclic Scaffolds
A novel palladium(0)‐catalyzed dearomative cyclization reaction of bromophenols with (1,n)‐diynes has been developed for building two new types of tricyclic architectures containing a quaternary carbon center. This method employs inexpensive bromophenols, and easily accessible tethered diynes. It exhibits a broad substrate scope and tolerates various functional groups. Preliminary results with commercially
New gold-catalyzed cyclization reactions of 1,6-diynes (2,2-dipropargylmalonates) are reported. Symmetrically (Me, Et) and unsymmetrically disubstituted (Me, Et, Ph) 1,6-diynes provided stereoselectively the Z-cyclopentylidene derivatives in 31−60% and 49−83% yield, respectively. High regioselectivity (97:3) was obtained for the cyclization of Me/Ph-substituted 1,6-diynes. A monosubstituted terminal
Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cycloaddition of Unsymmetrical α,ω-Diynes with Acenaphthylene
作者:Yukimasa Aida、Yu Shibata、Ken Tanaka
DOI:10.1021/acs.joc.7b03042
日期:2018.3.2
It has been established that a cationic rhodium(I)/(R)-BINAP complex catalyzes the asymmetric [2 + 2 + 2] cycloaddition of unsymmetrical α,ω-diynes with acenaphthylene at room temperature to give the corresponding chiral multicyclic compounds with high yields and ee values. Interestingly, enantioselectivity highly depended on the structures of α,ω-diynes used. The structural requirements of α,ω-diynes
Gold(I)-Catalyzed Intra- and Intermolecular Alkenylations of β-Yne-pyrroles: Facile Formation of Fused Cycloheptapyrroles and Functionalized Pyrroles
作者:Bin Pan、Xiaodong Lu、Chunxiang Wang、Yancheng Hu、Fan Wu、Boshun Wan
DOI:10.1021/ol500744k
日期:2014.4.18
An efficient gold(I)-catalyzed alkenylation of β-alkyne-substituted pyrroles is reported. The intramolecular reaction gives straightforward access to different types of seven-membered-ring-fused pyrroles with endo-selectivity, and the intermolecular reaction with alkynes provides functionalized pyrrole derivatives.