Remarkable contrast between chemospecificities in acid-mediated arylation of δ- and γ-ketocarboxylic acids was revealed: in the presence of P2O5–MsOH, TfOH, PPA, and MsOH, arylation of δ-ketocarboxylic acid 1A with arenes takes place at the carboxycarbonyl carbon, while that of γ-ketocarboxylic acid 1B takes place at the ketone carbonyl carbon, specifically.
2-(1-Benzotriazolyl)pyridine: A Robust Bidentate Ligand for the Palladium-Catalyzed CC (Suzuki, Heck, Fujiwara-Moritani, Sonogashira), CN and CS Coupling Reactions
作者:Akhilesh K. Verma、Rajeev R. Jha、Ritu Chaudhary、Rakesh K. Tiwari、Abhinandan K. Danodia
DOI:10.1002/adsc.201200583
日期:2013.2.1
designed and employed for the palladium-catalyzed CC (Suzuki, Heck, Fujiwara–Moritani, and Sonogashira), CN and CS coupling reactions. The ligand was found to be inexpensive, thermally stable, easy to synthesize from easily accessible starting materials on a multigram scale, show simplicity in use, and robustness in application, making this ligand effective for different coupling reactions. Suitably, the
设计了一种新型的双齿配体1-(吡啶-2-基)-1 H-苯并[ d ] [1,2,3]三唑,并用于钯催化的CC(Suzuki,Heck,Fujiwara– Moritani和Sonogashira),CN和CS偶联反应。发现该配体便宜,热稳定,易于以几克规模由容易获得的起始原料合成,显示出使用简单性和在应用中的坚固性,从而使该配体对于不同的偶联反应有效。适当地,苯并三唑环的NN键的供体能力和吡啶环的N上的孤对电子增强了配体的二齿能力。
Isopropylmagnesium chloride-promoted unilateral addition of Grignard reagents to β-diketones: one-pot syntheses of β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones
作者:Rui Yuan、Dan Zhao、Li-Yuan Zhang、Xiang Pan、Yan Yang、Pei Wang、Hong-Feng Li、Chao-Shan Da
DOI:10.1039/c5ob02072g
日期:——
unilateral additions of Grignardreagents to acyclic or cyclic β-diketones were effectively promoted by sub-stoichiometric amounts of i-PrMgCl to afford β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones, respectively. Also, the addition of Grignardreagents to acyclic β-diketones followed by a reaction with cyclic β-diketones in a one-pot process was put forward. The reaction mechanism was discussed
Two methods for the preparation of 2-cyclohexenones from resin-bound 1,3-cyclohexanedione
作者:Mark E. Fraley、Robert S. Rubino
DOI:10.1016/s0040-4039(97)00631-x
日期:1997.5
The addition of organolithium or Grignard reagents to vinylogous ester resin 1 followed by mild hydrolysis of product resins 2 provides 3-alkyl-2-cyclohexenones in high purity (>95%). Alternatively, conversion of 1 to vinyl triflate resin 4 followed by palladium-mediated couplings with aryl boronic acids and hydrolysis furnishes 3-aryl-2-cyclohexenones in lower yield, but exceptional purity.
The enantioselectivehydrogenation of endocyclic enones has been a historical problem for homogeneous catalysis. We herein report an efficient method to reduce endocyclic enones with molecular hydrogen. Catalyzed by a rhodium/Zhaophos complex, a variety of enones with five‐, six‐ or seven‐member ring were hydrogenated with high enantioselectivity (92%—99% ee). Excellent chemo‐ and enantioselectivity