Chemoselective CC Bond Cleavage of Epoxide Motifs: Gold(I)-Catalyzed Diastereoselective [4+3] Cycloadditions of 1-(1-Alkynyl)oxiranyl Ketones and Nitrones
作者:Tao Wang、Junliang Zhang
DOI:10.1002/chem.201002395
日期:2011.1.3
Cutting carbon! A novel facile strategy for the CCbondcleavage of oxiranylketones has been developed. Carbophilic gold(I) activation of the alkyne side chain mediates a heterocyclization and subsequent CCbondcleavage (see scheme).
Visible Light-Mediated Coupling of α-Bromochalcones with Alkenes
作者:Suva Paria、Viktor Kais、Oliver Reiser
DOI:10.1002/adsc.201400638
日期:2014.9.15
Photoredox catalyzed intermolecular couplings of α‐bromochalcones to olefins have been developed. Employing 1 mol% of the iridium complex Ir(ppy)3 as photocatalyst, vinyl radicals are generated from α‐bromochalcones as the key intermediate, which efficiently engage in a formal [4+2] cyclization with various alkenes. The resulting 3,4‐dihydronaphthalenes can be readily transformed to the corresponding
已经开发了光氧化还原催化的α-溴代查耳酮与烯烃的分子间偶联。使用1 mol%的铱络合物Ir(ppy)3作为光催化剂,乙烯基自由基是由α-溴代查耳酮作为关键中间体生成的,可以有效地与各种烯烃进行正式的[4 + 2]环化反应。生成的3,4-二氢萘可以很容易地转化为相应的萘,并进一步环化为5 H-苯并[ c ]芴。另外,如果烯烃在烯丙基位置具有合适的离去基团,则可以得到Heck型偶联产物与空间受阻更强的烯烃或烯丙基化产物。
Chiral N,N′-dioxide-Sc(NTf<sub>2</sub>)<sub>3</sub> complex-catalyzed asymmetric bromoamination of chalones with N-bromosuccinimide as both bromine and amide source
A chiral N,N[prime or minute]-dioxide-Sc(NTf2)3complex catalytic system has been developed to catalyze the asymmetric bromoamination reaction of chalones with N-bromosuccinimide.
Sc(OTf)<sub>3</sub>-Catalyzed Diastereoselective Formal [3+2] Cycloaddition Reactions of Alkynylcyclopropane Ketones with Electron-Rich Aromatic Aldehydes To Yield 2,5-<i>trans</i>-Tetrahydrofurans
作者:Chi Zhang、Muyun Xu、Jun Ren、Zhongwen Wang
DOI:10.1002/ejoc.201600233
日期:2016.5
the general [4+2] cycloaddition reactions of alkynylcyclopropane ketones reported in the literature, we report herein a Sc(OTf)3-catalyzed formal intermolecular [3+2] cycloaddition reaction of alkynylcyclopropane ketones with electron-rich aromatic aldehydes. 2,3,3,5-Tetrasubstituted tetrahydrofurans were obtained by this method, and the tetrahydrofuran skeleton was diastereoselectively constructed with
Indium‐Catalysed Transfer Hydrogenation for the Reductive Cyclisation of 2‐Alkynyl Enones towards Trisubstituted Furans
作者:Luomo Li、Sascha Kail、Sebastian M. Weber、Gerhard Hilt
DOI:10.1002/anie.202109266
日期:2021.10.25
Indiumtribromidecatalysed the transferhydrogenation from dihydroaromatic compounds, such as the commercially available γ-terpinene, to enones, which resulted in the cyclisation to trisubstituted furan derivatives. The reaction was initiated by a Michael addition of a hydride nucleophile to the enone subunit followed by a Lewis-acid-assisted cyclisation and the formation of a furan–indium intermediate
三溴化铟催化从二氢芳香族化合物(例如市售的γ-萜品烯)到烯酮的转移氢化,从而环化为三取代的呋喃衍生物。该反应是通过将氢化物亲核试剂迈克尔加成到烯酮亚基上引发的,然后进行路易斯酸辅助环化并形成呋喃-铟中间体和衍生自二氢芳族起始材料的Wheland中间体。该产物是通过 Wheland 配合物质子化形成的,并取代了三溴化铟取代基。此外,二氢芳香族 HD 替代物的位点特异性氘标记导致了产物的位点特异性标记,并通过 H-D 加扰提供了对反应机制的有用见解。