108716-00-3Relevant academic research and scientific papers
PdII/Novel Chiral Cinchona Alkaloid Oxazoline-Catalyzed Enantioselective Oxidative Cyclization of Aromatic Alkenyl Amides
Tian, Qinqin,Liu, Yulong,Wang, Xiaoyun,Wang, Xie,He, Wei
, p. 3850 - 3855 (2019/06/08)
A highly enantioselective PdII-catalyzed aza-Wacker oxidation tandem cyclization of aromatic nitrogen-containing dienes has been achieved in the presence of novel chiral cinchona alkaloid oxazoline ligands for the first time, affording chiral dihydroindole nitrogen-containing polycyclic compounds with good yields (up to 83 %), high diastereoselectivities (> 95:5 dr), and excellent enantioselectivities (up to 97 % ee).
A Synthetic Route to Chiral Benzo-Fused N-Heterocycles via Sequential Intramolecular Hydroamination and Asymmetric Hydrogenation of Anilino-Alkynes
Xu, Cong,Feng, Yu,Li, Faju,Han, Jiahong,He, Yan-Mei,Fan, Qing-Hua
, p. 3979 - 3990 (2019/11/14)
An efficient sequential intramolecular hydroamination/asymmetric hydrogenation reaction under catalysis of a single chiral ruthenium complex or a binary system consisting of achiral gold complex and chiral ruthenium complex has been reported. A diverse range of enantioenriched benzo-fused N-heterocycles, including 1,2,3,4-tetrahydroquinoline, indoline, and 2,3,4,5-tetrahydro-1H-benzo[b]azepine derivatives, were obtained from anilino-alkynes in high yields (up to 98%) with moderate to excellent enantioselectivities (up to 98% ee) under mild conditions. This protocol features good functional group tolerance and high atom economy. Furthermore, this catalytic protocol is applicable to gram-scale synthesis of a naturally occurring alkaloid, (-)-Angustureine.
2-(Phenylseleno)ethanesulfon-amide as a novel protecting group for aniline that can be deprotected by a radical reaction
Kihara, Nobuhiro,Mitsuhashi, Yuji,Sato, Makoto,Hirose, Shun-Ichi,Goudo, Erika,Uzawa, Yoshinori,Shirai, Natsumi,Hamamoto, Sari,Iwasaki, Ryo,Fujioka, Akane
supporting information, p. 2563 - 2566 (2016/06/06)
Anilines were protected as 2-(phenylseleno)ethanesulfonanilide (SeES anilide) via sulfonylation by 2-chlorosulfonyl chloride followed by the conjugate addition of benzeneselenol. The SeES anilide was deprotected by radical reduction using tributyltin hydride in the presence of AIBN. The corresponding anilines were obtained in high yields when the hydride and AIBN were added to the system slowly. Since the radical reaction proceeds under neutral conditions, chemoselective deprotection of the SeES group was accomplished. The SeES anilide was stable under various conditions, including some severe conditions.
Simple and convenient approach for synthesis of tetrahydroquinoline derivatives and studies on aza-Cope rearrangement
Rao Lingam, V.S. Prasada,Thomas, Abraham,Mukkanti, Khagga,Gopalan, Balasubramanian
, p. 1809 - 1828 (2011/06/20)
A simple and novel synthesis of 1,2,3,4-tetrahydroquinoline derivatives by polyphosphoric acid-assisted reaction of N-aryl allyl anilines prepared from anilines has been reported. The generality and scope of the approach has been demonstrated by extending it to the synthesis of 1,2,5,6-tetrahydro-4H- pyrrolo[3,2,1-ij]quinoline (lilolidine) and 2,3,6,7-tetrahydro-1H,5H-pyrido[3,2, 1-ij]quinoline (julolidine). Further, Lewis acid- mediated aza-Cope rearrangement of various N-aryl allyl anilines has been demonstrated.
Nucleophilic substitution reactions of alcohols with use of montmorillonite catalysts as solid Bronsted acids
Motokura, Ken,Nakagiri, Nobuaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
, p. 6006 - 6015 (2008/02/10)
(Chemical Equation Presented) We have developed an environmentally benign synthetic approach to nucleophilic substitution reactions of alcohols that minimizes or eliminates the formation of byproducts, resulting in a highly atom-efficient chemical process. Proton- and metal-exchanged montmorillonites (H- and Mn+-mont) were prepared easily by treating Na +-mont with an aqueous solution of hydrogen chloride or metal salt, respectively. The H-mont possessed outstanding catalytic activity for nucleophilic substitution reactions of a variety of alcohols with anilines, because the unique acidity of the H-mont catalyst effectively prevents the neutralization by the basic anilines. In addition, amides, indoles, 1,3-dicarbonyl compounds, and allylsilane act as nucleophiles for the H-mont-catalyzed substitutions of alcohols, which allowed efficient formation of various C-N and C-C bonds. The solid H-mont was reusable without any appreciable loss in its catalytic activity and selectivity. Especially, an Al3+-mont showed high catalytic activity for the α-benzylation of 1,3-dicarbonyl compounds with primary alcohols due to cooperative catalysis between a protonic acid site and a Lewis acidic Al3+ species in its interlayer spaces.
Photogeneration and reactivity of 1,n-diphenyl-1,n-azabiradicals
Leo, Edgar A.,Domingo, Luis R.,Miranda, Miguel A.,Tormos, Rosa
, p. 4439 - 4444 (2007/10/03)
The 1,5-diphenyl-1,5-azapentanediyl biradical Ia was generated by photolysis of 1,2-diphenylazacyclopentane (pyrrolidine 1a). Among the reaction pathways followed by Ia, C-N bond reformation with ring closure was found to be the predominating process, as determined by separate irradiation of either of the pure enantiomers of 1a. Disproportionation was a minor process and took place only via H abstraction by the C5 benzylic radical. Another minor pathway was C5-aryl coupling, with formation of 5-phenyl-2,3,4,5-tetrahydro-1H-benzo[b] azepine (4a), which is equivalent to photo-Claisen rearrangement of 1a. Likewise, the 1,4-diphenyl-1,4-azabutanediyl biradical Ib was generated by photolysis of 1,2-diphenylazacyclobutane (azetidine 1b). This species underwent predominating C2-C3 cleavage, as indicated by the extensive styrene formation. Although NI-C4 bond reformation also took place, this is not the major pathway occurring from Ib. Besides, C4-aryl coupling to give 4-phenyl-1,2,3,4- tetrahydroquinoline (4b) was also observed. All the possible reaction pathways were theoretically studied at the UB3LYP/6-31G* computational level; the results were found to be in good agreement with the experimental observations.
Electron transfer versus proton transfer in excited states of bichromophoric aniline/olefin systems
Benali, Otman,Miranda, Miguel A.,Tormos, Rosa
, p. 2317 - 2322 (2007/10/03)
Photolysis of 2-allylaniline (1a) and trans-2-cinnamylaniline (2a) produced mainly the five- or the six-membered ring products 3a or 9a, respectively. Compound 1b, the N-acetyl derivative of la, preferentially underwent photo-Fries rearrangement of the anilide moiety, while - in contrast - the analogous compound 2b, derived from 2a, displayed competition between photocyclisation and double-bond isomerisation. The latter process, characteristic of the styrene chromophore, largely predominated in the case of 2c, the N-trifluoroacetyl derivative of 2a, while the allyl analogue 1c was essentially unreactive. The photochemical behaviour of the cis-cinnamyl compounds 7a and 7b was analogous to that of their trans isomers 2a and 2b, although double bond isomerisation occurred to a smaller extent. Thus, the introduction of electron-withdrawing acyl groups decreased photocyclisation. The nature of the excited states involved in the photochemistry of 1a-c, 2a-c and 7a and 7b was studied by fluorescence measurements. The most remarkable observation was the formation of intramolecular charge-transfer exciplexes in the cases of 1a, 2a, 2b, 7a and 7b. The exciplex bands of the cinnamyl compounds 2a, 2b, 7a and 7b in acetonitrile were considerably red-shifted (maxima at ca. 500 nm). A satisfactory correlation of the photochemical and photophysical data could be achieved by considering that photocyclisation took place when clear exciplex emission was observed. Alltogether, the above data strongly supported the involvement of an excited state electron-transfer mechanism in the photocyclisation of aniline/olefin bichromophoric systems. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
