Studies in photochemistry. Part VII. The photocyclisation of some nuclear-substituted stilbenes to substituted phenanthrenes
作者:E. V. Blackburn、C. E. Loader、C. J. Timmons
DOI:10.1039/j39680001576
日期:——
Photocyclodehydrogenation of trans-9-styryl-1,2,3,4,5,6,7,8-octahydroanthracene in cyclohexane solution formed a mixture of 11-butyl- and 11-but-3-enyl-1,2,3,4-tetrahydrochrysene in very small yield, identified by their i.r., u.v., 1H n.m.r., and mass spectra. 2,4,6-Trimethylstilbene photocyclised to 1,3-dimethylphenanthrene with the elimination of a methyl group. 3,3′,5,5′-Tetramethylstilbene formed
在环己烷溶液中反式-9-苯乙烯基-1,2,3,4,5,6,7,8-八氢蒽的光环脱氢反应形成11-丁基-和11-丁-3-烯基-1,2,3的混合物通过其ir,uv,1 H nmr和质谱鉴定的1,4-四氢丙烯收率非常低。2,4,6-三甲基sti光环化为1,3-二甲基菲并消除了甲基。当在环己烷溶液中照射时,3,3',5,5'-四甲基sti形成了2,4,5,7-四甲基菲。类似地,4,4′-二溴-和4,4′-二氰基-sti形成相应的3,6-二取代的菲。
The effect of aryl substituents on arylcarbene reactivity
and cyclohexane) and the relative rate of O—H insertion into methanol to stereospecific cyclopropanation of the olefin to C—H insertion into cyclohexane are calculated from the ratios of products and substrates. It is found (i) that the reactivities of the substrates decrease in the order of methanol, olefin and cyclohexane and (ii) that electron-donating substituents generally lead to reaction with
Palladium-Catalyzed Cross-Coupling Reactions of Potassium Alkenyltrifluoroborates with Organic Halides in Aqueous Media
作者:Emilio Alacid、Carmen Nájera
DOI:10.1021/jo802356n
日期:2009.3.20
cross-coupled with aryl and heteroaryl bromides using 1 mol % Pd loading of 4-hydroxyacetophenone oxime derived palladacycle or Pd(OAc)2 as precatalysts, K2CO3 as base, and TBAB as additive and water reflux under conventional or microwave heating to afford styrenes, stilbenoids, and alkenylbenzenes. These borates can be cross-coupled diastereoselectively with allyl and benzylchlorides using KOH as base
乙烯基和烯基三氟硼酸钾与芳基和杂芳基溴化物进行交叉偶联,使用1摩尔%的4-羟基苯乙酮肟衍生的palladacycle或Pd(OAc)2作为Pd的前催化剂,K 2 CO 3在常规或微波加热下,作为碱和TBAB作为添加剂并进行水回流,得到苯乙烯,二苯乙烯类化合物和烯基苯。这些硼酸盐可以在丙酮水(3:2)中,在50°C和0.1 mol%Pd负载下,使用KOH作为碱,与烯丙基氯和苄基氯进行非对映选择性交联,分别得到相应的1,4-二烯和烯丙基芳烃。这些简单的无膦反应条件允许通过萃取分离包含58-105 ppm Pd的产物,在多达五次运行中从水相中回收钯。
Synthesis of Polysubstituted Imidazoles and Pyridines<i>via</i>Samarium(III) Triflate-Catalyzed [2+2+1] and [4+2] Annulations of Unactivated Aromatic Alkenes with Azides
作者:Yingchun Wang、Jiuling Li、Yan He、Yuyang Xie、Hengshan Wang、Yingming Pan
DOI:10.1002/adsc.201500584
日期:2015.10.12
Samarium(III) triflate-catalyzed [2+2+1] and [4+2] annulations have been identified for the preparation of fully substituted imidazoles and 2,3,5-trisubstituted pyridines from the readily available unactivatedaromaticalkenes and azidomethyl aromatics. These reactions proceeded smoothly with one- or two-nitrogen synthons to afford a range of two types of skeletally distinct N-heterocycles in good