61895-27-0Relevant academic research and scientific papers
Catalytic enantioselective synthesis of chiral spirocyclic 1,3-diketones: Via organo-cation catalysis
Zhang, Xiao-Yan,Shao, Ya-Ping,Guo, Bao-Kuan,Zhang, Kun,Zhang, Fu-Min,Zhang, Xiao-Ming,Tu, Yong-Qiang
supporting information, p. 11233 - 11235 (2021/11/09)
An SPA-triazolium bromide-catalyzed transannular C-acylation of enol lactones is presented. This methodology provides convenient access to a range of enantioenriched spirocyclic 1,3-diketones in moderate to high yields and enantioselectivities and features a broad substrate scope in terms of enol lactones. The catalytic capability of this triazolium salt catalyst is also demonstrated in this enantioselective transformation, which could inspire its further application. This journal is
Highly Enantioselective Oxidation of Spirocyclic Hydrocarbons by Bioinspired Manganese Catalysts and Hydrogen Peroxide
Qiu, Bin,Xu, Daqian,Sun, Qiangsheng,Miao, Chengxia,Lee, Yong-Min,Li, Xiao-Xi,Nam, Wonwoo,Sun, Wei
, p. 2479 - 2487 (2018/03/13)
Bioinspired manganese complexes have emerged as attractive catalysts for a number of selective oxidation reactions over the past several decades. In the present study, we report the enantioselective oxidation of spirocyclic compounds with manganese complexes bearing tetradentate N4 ligands as catalysts and aqueous H2O2 as a terminal oxidant under mild conditions; spirocyclic tetralone (1a) and its derivatives bearing electron-donating and -withdrawing substituents are converted to their corresponding chiral spirocyclic β,β′-diketones with high yields and enantioselectivities. Spirocyclic indanones are also converted to the β,β′-spirobiindanones with high enantioselectivities. Indeed, the reaction expands the diversity of chiral spirocyclic diketones via a late-stage oxidative process. In addition, it is of importance to note that the catalytic reaction can be easily scaled up and the chiral spirocyclic β,β′-diketones can be transformed into diol products. In mechanistic studies, we have shown that (1) ketones were yielded as products via the initial formation of alcohols, followed by the further oxidation of the alcohols to ketones, (2) hydrogen atom (H atom) abstraction from the methylene C-H bonds of 1a by a putative Mn(V)-oxo intermediate was proposed to be the rate-determining step, and (3) the C-H bond hydroxylation of 1a by the Mn(V)-oxo species was proposed to occur via oxygen rebound mechanism. On the basis of these results, we have proposed a plausible mechanism for the selective C-H bond oxidation of hydrocarbons by bioinspired manganese catalysts and hydrogen peroxide.
Syntheses, Structures and Optoelectronic Properties of Spiroconjugated Cyclic Ketones
Wilbuer, Jennifer,Schnakenburg, Gregor,Esser, Birgit
, p. 2404 - 2412 (2016/06/01)
Synthetic investigations towards spiroconjugated ketones and derivatives thereof are presented. These studies led to the development of a short procedure for the synthesis of spiroconjugated tetraketone 1 in two steps with 10 % overall yield and the first-time synthesis of spirocyclic trindone 2. The optoelectronic properties of these compounds based on spectroscopic and electrochemical measurements in combination with DFT calculations as well as their molecular structures in the solid state are presented and discussed.
Catalytic Enantioselective Synthesis of C1- and C2-Symmetric Spirobiindanones through Counterion-Directed Enolate C-Acylation
Rahemtulla, Benjamin F.,Clark, Hugh F.,Smith, Martin D.
, p. 13180 - 13183 (2016/10/30)
A catalytic enantioselective route to C1- and C2-symmetric 2,2′-spirobiindanones has been realized through an intramolecular enolate C-acylation. This reaction employs a chiral ammonium counterion to direct the acylation of an in situ generated ketone enolate with a pentafluorophenyl ester. This reaction constitutes the first example of a direct catalytic enantioselective C-acylation of a ketone and provides an efficient and highly enantioselective route to axially chiral spirobiindanediones. These products can be diastereoselectively derivatized, offering access to a range of functionalized spirocyclic architectures.
Exciton chirality method in vibrational circular dichroism
Taniguchi, Tohru,Monde, Kenji
supporting information; experimental part, p. 3695 - 3698 (2012/04/11)
The interaction of two IR chromophores yields a strong vibrational circular dichroism couplet whose sign reflects the absolute configuration of the molecule. We present a method to determine absolute configuration of a chiral molecule based on this couplet without need of theoretical calculation. Not only can this method analyze various molecules whose absolute configuration is difficult to determine by other spectroscopic methods, but also it can significantly enhance VCD signals.
Synthesis of a novel spiro bisphosphinite ligand and its application in Rh-catalyzed asymmetric hydrogenation
Guo, Zhenqiu,Guan, Xiaoyu,Chen, Zhiyong
, p. 468 - 473 (2007/10/03)
A novel, chiral bisphosphinite ligand (R)-SpiroBIP has been synthesized. The rhodium complex of the ligand was found to be highly enantioselective in the asymmetric hydrogenation of α-dehydroamino acid derivatives.
New '2-phenylnaphthalene'-mediated synthesis of benzo[b]naphtho[2,3-d] furan-6,11-diones and 6-oxa-benzo[a]anthracene-5,7,12-triones: First total synthesis of 6-oxa-benzo[a]anthracen-5-ones
Martínez, Ana,Fernández, Marcos,Estévez, Juan C.,Estévez, Ramón J.,Castedo, Luis
, p. 1353 - 1362 (2007/10/03)
We describe here a novel synthesis of benzo[b]naphtho[2,3-d]furan-6,11- diones based on the heteroannulation of 2-(2-bromophenyl)-3-hydroxy-1,4- naphthoquinones. The naphthoquinones were prepared from 3-(2-bromophenyl) naphthalen-2-ols, which were obtained by intramolecular aldol condensation of 2-[3-(2-bromophenyl)-2-oxo-propyl]benzaldehydes. Alternatively, benzo[b]naphtho[2,3-d]furan-6,11-diones were obtained more directly and efficiently by cyclization of 3-(2-bromophenyl)naphthalen-2-ols to benzo[b]naphtho[2,3-d]furans and oxidation of the resulting compounds. Furthermore, the first 6-oxabenzo[a]anthracen-5-one described was similarly obtained from 2-[3-(2-formylphenyl)-2-oxopropyl]benzoic acid and oxidized to 6-oxa-benzo[a]anthracene-5,7,12-trione.
Synthesis, structure, and nucleophile-induced rearrangements of spiroketones
Maslak, Przemyslaw,Varadarajan, Sridhar,Burkey, Jeffrey D.
, p. 8201 - 8209 (2007/10/03)
Three tetraketones based on the 2,2'-spirobiindan-1,1',3,3'-tetraone skeleton were prepared and investigated. All three compounds show spiroconjugation between their perpendicular π-networks. The interaction results in lowering of the energy of the LUMO of the systems by ca. 0.2-0.3 eV as compared to non-spiroconjugated models. The spiroketones are susceptible to nucleophile-induced retro-Claisen condensations that lead to molecular rearrangements destroying spiro connectivity.
An improved synthesis and resolution of (±)-cis,cis-2,2'-spirobiindane-1,1'-diol
Nieman,Keay
, p. 1575 - 1583 (2007/10/02)
(±)-cis,cis-2,2'-spirobiindane-1,1'-diol (1) is synthesized stereoselectively in four steps beginning with 1-indanone in 68% overall yield. An improved resolution of diol 1 is described by preparing and separating diastereomeric mono-esters of 1 using (2S)-O-(tert-butyldimethylsilyl)mandeloyl chloride (10).
Aromatic Spiranes, XVI: Syntheses of Mono- and Dianellated 2,2'-Spirobiindane-1,1'diones
Neudeck, Horst K.
, p. 597 - 622 (2007/10/02)
The spiroketones 19, 21, 24, 27, and 31 were prepared by cyclisation of the dicarboxylic acids and their acid chlorides, resp., (18, 20, 22, 23, 25, 26, 28, and 30) with polyphosphoric acid (PPA) or SnCl4.The latter compounds were synthesized by alkylation of the appropriate β-keto esters 10, 11, 12, and 13 with the "benzyl chlorides" 14, 15, 16, and subsequent retro-Claisen reaction.The spiro compounds 21a and 39 were obtained by PPA-cyclisation of the keto acids 35 and 38, which in turn were prepared by aldol-reaction of the ketones s-hydrindacen-1-on and 9a with phthalaldehydic acid to the olefinic keto acids 33 and 36 followed by catalytic hydrogenation. - Keywords: Indane-1-one; s-Hydrindacene-1-one; Tetrahydrobenzoindane-1-one; β-Keto esters; Phthalaldehydic acid; Spiro cyclisation; 2,2'-Spirobiindane-1,1'-diones; 1H-nmr spectra; Mass spectra
