Platinum and Ruthenium Chloride-Catalyzed Cycloisomerization of 1-Alkyl-2-ethynylbenzenes: Interception of π-Activated Alkynes with a Benzylic C−H Bond
摘要:
Air-stable and commercially available alkynophilic metal salts, such as PtCl2, PtCl4, and [RuCl2(CO)(3)](2), catalyze the cycloisomerization of 1-alkyl-2-ethynylbenzenes to produce Substituted indenes even at all ambient temperature. Electrophilically activated alkynes can be intercepted by simple benzylic C-H bonds at primary, secondary, and tertiary carbon centers. Mechanistic studies, such as labeling studies and kinetic isotope and substituent effects, indicate that the cycloisomerization proceeds through the formation of a vinylidene intermediate and turnover-limiting 1,5-shift of benzylic hydrogen.
Rhodium(II)-Catalyzed and Thermally Induced Intramolecular Migration of<i>N</i>-Sulfonyl-1,2,3-triazoles: New Approaches to 1,2-Dihydroisoquinolines and 1-Indanones
作者:Run Sun、Yu Jiang、Xiang-Ying Tang、Min Shi
DOI:10.1002/chem.201504914
日期:2016.4.11
New rhodium(II)‐catalyzed or thermally induced intramolecular alkoxy group migration of N‐sulfonyl‐1,2,3‐triazoles has been developed, affording divergent synthesis of 1,2‐dihydroisoquinoline and 1‐indanone derivatives according to different conditions. N‐Sulfonyl keteneimine is the key intermediate for the synthesis of dihydroisoquinoline, whereas the aza‐vinyl carbene intermediate results in the
A photocatalyticsulfonylcarbocyclization of terminal alkynesusingSEt as a tracelessdirectinggroup is developed, providing a facile access to highly substituted cyclopentenes and indenes from readily available starting materials. It represents a new advance on anti-Baldwin 5-endo-trig radical cyclization of all-carbon systems, which may be valuable for the fast construction of five-membered carbocycles
开发了使用 SEt 作为无痕导向基团的末端炔烃的光催化磺酰基碳环化,提供了从容易获得的起始材料中轻松获得高度取代的环戊烯和茚的方法。它代表了全碳系统的反鲍德温 5-endo-trig 自由基环化的新进展,这可能对快速构建五元碳环很有价值。
Addition of benzyl ethers to alkynes: a metal-free synthesis of 1<i>H</i>-isochromenes
Bromotrimethylsilane (TMSBr)-promoted intramolecular cyclization of (o-arylethynyl)benzylethers to form 1H-isochromenes at room temperature is reported. Further studies indicated that vinyl carbocations are the reaction intermediates which are stabilized by the conjugated aryl groups. Thus, O-addition of benzylethers/tetrahydropyrans to alkynes was achieved under metal-free, acidic conditions. These
报道了溴代三甲基硅烷 (TMSBr) 促进的 ( o -arylethynyl) 苄基醚在室温下分子内环化形成 1 H-异色烯。进一步的研究表明,乙烯基碳阳离子是由共轭芳基稳定的反应中间体。因此,在无金属、酸性条件下实现了苄基醚/四氢吡喃与炔烃的O-加成。这些反应条件与炔基普林斯反应相容;因此,使用一锅法直接由炔基苯甲醛和炔醇生产1 H-异色烯。
Rhodium(II)-Catalysed Skeletal Rearrangement of Ether Tethered<i>N</i>-Sulfonyl 1,2,3-Triazoles: a Rapid Approach to 2-Aminoindanone and Dihydroisoquinoline Derivatives
The skeletalrearrangement of ether tethered N‐sulfonyl‐1,2,3‐triazoles has been achieved by rhodium(II) catalysis. This method offers a rapid entry to 2‐aminoindanone and dihydroisoquinoline architectures which can be further transformed to other valuable building blocks, such as vicinal aminoindanols, isoquinolines and isoquinolinones. A pathway involving an azavinyl rhodium carbene intermediate