100461-77-6Relevant academic research and scientific papers
Triazatriangulenium cations: Highly stable carbocations for phase-transfer catalysis
Nicolas, Cyril,Lacour, Jerome
, p. 4343 - 4346 (2006)
(Chemical Equation Presented) Highly stable triazatriangulenium carbocations, of pKR+ higher than 20, can be used as novel phase-transfer catalysts for several classical organic reactions, their intrinsic stability in strongly basic and nucleophilic conditions rendering this novel use feasible.
Catalytic Asymmetric Homologation of Ketones with α-Alkyl α-Diazo Esters
Tan, Fei,Pu, Maoping,He, Jun,Li, Jinzhao,Yang, Jian,Dong, Shunxi,Liu, Xiaohua,Wu, Yun-Dong,Feng, Xiaoming
, p. 2394 - 2402 (2021/02/16)
The homologation of ketones with diazo compounds is a useful strategy to synthesize one-carbon chain-extended acyclic ketones or ring-expanded cyclic ketones. However, the asymmetric homologation of acyclic ketones with α-diazo esters remains a challenge due to the lower reactivity and complicated selectivity. Herein, we report the enantioselective catalytic homologation of acetophenone and related derivatives with α-alkyl α-diazo esters utilizing a chiral scandium(III) N,N′-dioxide as the Lewis acid catalyst. This reaction supplies a highly chemo-, regio-, and enantioselective pathway for the synthesis of optically active β-keto esters with an all-carbon quaternary center through highly selective alkyl-group migration of the ketones. Moreover, the ring expansion of cyclic ketones was accomplished under slightly modified conditions, affording a series of enantioenriched cyclic β-keto esters. Density functional theory calculations have been carried out to elucidate the reaction pathway and possible working models that can explain the observed regio- and enantioselectivity.
Radical-Polar Crossover Annulation: A Platform for Accessing Polycyclic Cyclopropanes
Milligan, John A.,Burns, Kevin L.,Le, Anthony V.,Polites, Viktor C.,Wang, Zheng-Jun,Molander, Gary A.,Kelly, Christopher B.
supporting information, p. 242 - 247 (2019/12/11)
Photoredox-mediated radical/polar crossover (RPC) processes provide unique solutions to challenging annulations. Herein, we describe an approach to the cyclopropanation of olefins that are embedded within bicyclic scaffolds. Whereas these systems are noto
Aromatic Spiranes, XVII: Syntheses of Anellated and Substituted 2,2'-Spirobiindane-1-ones and 4,5'-Disubstituted 2,2'-Spirobiindanes
Neudeck, Horst K.
, p. 623 - 642 (2007/10/02)
The spiroketones 9, 16, and 28 were prepared by cyclisation of the carboxylic acids 7c, 13b, and 25c and their acid chlorides, resp. (7d, 13c, and 25d) with polyphosphoric acid (PPA) or SnCl4.The precursors of the latter compounds were synthesized by alky
Asymmetric Alkylation of β-Keto Esters with Optically Active Sulfonium Salts
Umemura, Kazuyuki,Matsuyama,Haruo,Watanabe, Nobuko,Kobayashi, Michio,Kamigata, Nobumasa
, p. 2374 - 2383 (2007/10/02)
Alkylation of the cyclic β-keto ester2-(methoxycarbonyl)-1-indanone (2) with racemic alkylsulfonium salts 1a-h gave 2-alkylindanones 3 and 4 in 60-96percent yields.The relative reactivities of the alkyl substituents of aryldialkylsulfonium salts 1e and 1f were quite different from those in SN2 alkylations.Asymmetric induction occured upon alkylation of 2 with optically active sulfonium salts. (R)-2-Ethyl-2-(methoxycarbonyl)cyclohexanone (11) was obtained in up to 16percent ee by alkylation of the enolate ion of 2-(methoxycarbonyl)cyclohexanone (9) with optically active (R)-(+)-(p-chlorophenyl)ethylmethylsulfonium d-10-camphorsulfonate (1k).Alkylation of the enolate ion of 2 with sulfonium salts containing optically active alkyl groups afforded C-alkylated products with inversion of configuration at the asymmetric alkyl carbon atom.These alkylations appear to proceed via an S-O sulfurane intermediate or a tight ion pair with subsequent stereoselective alkyl migration to the enolate.
NOVEL ASYMMETRIC ALKYLATION OF CYCLIC β-KETO ESTERS WITH OPTICALLY ACTIVE SULFONIUM SALTS
Kobayashi, Michio,Umemura, Kazuyuki,Watanabe, Nobuko,Matsuyama, Haruo
, p. 1067 - 1070 (2007/10/02)
A new asymmetric alkylation of cyclic β-keto esters with optically active sulfonium salts, which are easily prepared by optical resolution methods, has been investigated.Relative reactivities for alkyl substituents are found to be quite different from tho
