- 11-Substituted 2,3-dimethoxy-8,9-methylenedioxybenzo[i]phenanthridine derivatives as novel topoisomerase I-targeting agents
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Several 11-substituted benzo[i]phenanthridine derivatives were synthesized, and their TOP1-targeting activity and cytotoxicity were assessed. Comparative data indicate that TOP1-targeting was often the primary molecular target associated with their cytoto
- Feng, Wei,Satyanarayana, Mavurapu,Tsai, Yuan-Chin,Liu, Angela A.,Liu, Leroy F.,LaVoie, Edmond J.
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- Expedient Synthesis of Bridged Bicyclic Nitrogen Scaffolds via Orthogonal Tandem Catalysis
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Bridged nitrogen bicyclic skeletons have been accessed via unprecedented site- and diastereoselective orthogonal tandem catalysis from readily accessible reactants in a step economic manner. Directed Pd-catalyzed γ-C(sp3)-H olefination of aminocyclohexane with gem-dibromoalkenes, followed by a consecutive intramolecular Cu-catalyzed amidation of the 1-bromo-1-alkenylated product delivers the interesting normorphan skeleton. The tandem protocol can be applied on substituted aminocyclohexanes and aminoheterocycles, easily providing access to the corresponding substituted, aza- and oxa-analogues. The Cu catalyst of the Ullmann-Goldberg reaction additionally avoids off-cycle Pd catalyst scavenging by alkenylated reaction product. The picolinamide directing group stabilizes the enamine of the 7-alkylidenenormorphan, allowing further product post functionalizations. Without Cu catalyst, regio- and diastereoselective Pd-catalyzed γ-C(sp3)-H olefination is achieved.
- Bheemireddy, Narendraprasad Reddy,Biswas, Sovan,Evano, Gwilherm,Maes, Bert U. W.,Van Steijvoort, Ben F.,Waeterschoot, Marjo
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supporting information
p. 21988 - 21996
(2021/08/13)
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- Nickel-Catalyzed, Regio- and Enantioselective Benzylic Alkenylation of Olefins with Alkenyl Bromide
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A NiH-catalyzed migratory hydroalkenylation reaction of olefins with alkenyl bromides has been developed, affording benzylic alkenylation products with high yields and excellent chemoselectivity. The mild conditions of the reaction preclude olefinic products from undergoing further isomerization or subsequent alkenylation. Catalytic enantioselective hydroalkenylation of styrenes was achieved by using a chiral bisoxazoline ligand.
- Liu, Jiandong,Gong, Hegui,Zhu, Shaolin
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supporting information
p. 4060 - 4064
(2020/12/25)
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- Total Synthesis of Indolizidine Alkaloids via Nickel-Catalyzed (4 + 2) Cyclization
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A Ni-catalyzed (4 + 2) cycloaddition of alkynes and azetidinones toward piperidinones was used as key reaction in the enantioselective synthesis of naturally occurring indolizidine alkaloids. The reaction benefits from the use of an easily accessible azet
- Renner, Jonas,Thakur, Ashish,Rutz, Philipp M.,Cowley, Jacob M.,Evangelista, Judah L.,Kumar, Puneet,Prater, Matthew B.,Stolley, Ryan M.,Louie, Janis
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supporting information
p. 924 - 928
(2020/02/04)
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- The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
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Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
- Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
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supporting information
(2019/12/05)
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- Thermal decarboxylative Nazarov cyclization of cyclic enol carbonates involving chirality transfer
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Decarboxylative Nazarov cyclization of chiral cyclic enol carbonates proceeded to afford chiral 2-cyclopentenones with excellent chirality transfer under thermal conditions without any catalyst. Interestingly, the thermal decarboxylative Nazarov cyclization furnished the desired product with better chirality transfer than the Lewis acid-catalyzed reaction.
- Kozuma, Akane,Komatsuki, Keiichi,Saito, Kodai,Yamada, Tohru
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supporting information
p. 60 - 63
(2019/12/12)
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- Stereoselective Synthesis of Highly Substituted Conjugated Dienes via Pd-Catalyzed Carbonylation of 1,3-Diynes
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The stereoselective synthesis of conjugated dienes was realized for the first time via Pd-catalyzed alkoxycarbonylation of easily available 1,3-diynes. Key to success is the utilization of the specific ligand 1,1′-ferrocenediyl-bis(tert-butyl(pyridin-2-yl)phosphine) (L1), which allows this novel transformation to proceed at room temperature. A range of 1,2,3,4-tetrasubstituted conjugated dienes are obtained in this straightforward access in high yields and selectivities. The synthetic utility of the protocol is showcased in the concise synthesis of several important intermediates for construction of natural products rac-cagayanin, rac-galbulin, rac-agastinol, and cannabisin G.
- Liu, Jiawang,Yang, Ji,Baumann, Wolfgang,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 10683 - 10687
(2019/07/04)
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- Cs2CO3-Mediated Vicinal Thiosulfonylation of 1,1-Dibromo-1-Alkenes with Thiosulfonates: An Expedient Synthesis of (E)-1,2-Thiosulfonylethenes
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A new and highly efficient vicinal thiosulfonylation of 1,1-dibromo-1-alkenes with thiosulfonates in the presence of cesium carbonate has been developed. The metal-free diheterofunctionalization is an operationally simple to access a wide range of (E)-1,2-thiosulfonylethenes (α-aryl-β-thioarylvinyl sulfones) in moderate to high yields with high levels of stereoselectivities. Further, scalable reactions have been demonstrated for this transformation, thus illustrating its efficiency and practicality. (Figure presented.).
- Reddy, Raju Jannapu,Kumari, Arram Haritha,Kumar, Jangam Jagadesh,Nanubolu, Jagadeesh Babu
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supporting information
p. 1587 - 1591
(2019/02/16)
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- With α - glucosidase inhibitory activity of aryl benzofuran derivatives
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The invention belongs to the field of pharmaceutical chemistry, relates to a glucosidase inhibitory activity of α - aryl benzofuran derivatives and preparation method, and the derivatives in the prevention and/or for treating 2 type diabetes mellitus, med
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Paragraph 0082; 0084; 0085
(2019/01/08)
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- [Cu]-catalyzed direct coupling of dibromoalkenes: Synthesis of symmetrical 1,3-diynes and triazoles
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An efficient [Cu]-catalyzed homocoupling of 1,1-dibromoalk-1-enes is described for the synthesis of symmetrical 1,3-diyines. The method showed good substrate scope and amenable to aryl and heteroaryl systems. Significantly, the strategy was also successfully applied to the sequential one-pot synthesis of triazoles.
- Mahendar, Lodi,Ramulu, Bokka Venkat,Satyanarayana, Gedu
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p. 1151 - 1158
(2017/06/13)
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- The Dual Role of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in the Synthesis of Terminal Aryl- and Styryl-Acetylenes via Umpolung Reactivity
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The dual role of the bicyclic amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was demonstrated in a synthesis of terminal aryl- and styryl-acetylenes. Mechanistically, a tandem process involving elimination/Umpolung/protonation occurs in a single step to generate terminal aryl- and styryl-acetylenes from geminal dibromoalkenes. The key to the success of this transformation lies in the organobase-mediated generation of the acetylide from the 1-bromoalkynes at room temperature. The unique characteristics of DBU as an inherently safer reagent make it an attractive alternative to previous systems wherein required pyrophoric reagents and nonambient temperatures remain unsolved issues. The procedure does not work for the synthesis of alkyl-acetylenes.
- Morri, Ashok Kumar,Thummala, Yadagiri,Doddi, Venkata Ramana
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supporting information
p. 4640 - 4643
(2015/09/28)
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- Antioxidant activity and inhibition of α-glucosidase by hydroxyl-functionalized 2-arylbenzo[b]furans
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This study synthesized a series of hydroxyl-functionalized 2-arylbenzo[b]furans based on the structure of tournefolic acid A and evaluated them for antioxidant and a-glucosidase inhibitory activities. Compounds 5a, 5e, and 5n showed remarkable inhibition
- Hsieh, Jung-Feng,Lin, Wei-Jen,Huang, Kai-Fa,Liao, Jiahn-Haur,Don, Ming-Jaw,Shen, Chien-Chang,Shiao, Young-Ji,Li, Wen-Tai
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p. 443 - 451
(2015/03/04)
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- Minimizing Aryloxy Elimination in RhI-Catalyzed Asymmetric Hydrogenation of β-Aryloxyacrylic Acids using a Mixed-Ligand Strategy
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The first example of efficient asymmetric hydrogenation of challenging β-aryloxyacrylic acids was realized using a RhI-complex based on the heterocombination of a readily available chiral monodentate secondary phosphine oxide (SPO) and an achiral monodentate phosphine ligand as the catalyst. Excellent enantioselectivities (92->99% ee) were achieved for a wide variety of chiral β-aryloxypropionic acids with minor aryloxy elimination in most cases. The resultant products were readily transformed into biologically active compounds through simple synthetic manipulations.
- Li, Yang,Wang, Zheng,Ding, Kuiling
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supporting information
p. 16387 - 16390
(2015/11/09)
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- Nickel-catalyzed asymmetric reductive cross-coupling between vinyl and benzyl electrophiles
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A Ni-catalyzed asymmetric reductive cross-coupling between vinyl bromides and benzyl chlorides has been developed. This method provides direct access to enantioenriched products bearing aryl-substituted tertiary allylic stereogenic centers from simple, stable starting materials. A broad substrate scope is achieved under mild reaction conditions that preclude the pregeneration of organometallic reagents and the regioselectivity issues commonly associated with asymmetric allylic arylation.
- Cherney, Alan H.,Reisman, Sarah E.
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supporting information
p. 14365 - 14368
(2014/12/11)
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- Autotandem catalysis: Synthesis of pyrroles by gold-catalyzed cascade reaction
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A novel synthesis of substituted pyrroles by a gold(I)-catalyzed cascade reaction has been developed. The reaction proceeded with an autotandem catalysis consisting of an initial addition of gold-acetylide to an acetal moiety and was followed by gold-catalyzed 5-endo-dig cyclization and aromatization. Gold catalysts play a dual role in activating nucleophilicity or electrophilicity of terminal acetylenes by forming gold-acetylides or by π-coordination. The formal (3 + 2) annulation of two components provided a variety of substituted pyrroles in a modular fashion.
- Ueda, Hirofumi,Yamaguchi, Minami,Kameya, Hiroshi,Sugimoto, Kenji,Tokuyama, Hidetoshi
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supporting information
p. 4948 - 4951
(2015/04/27)
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- Asymmetric hydroformylation of Z -Enamides and enol esters with rhodium-bisdiazaphos catalysts
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Asymmetric hydroformylation (AHF) of Z-enamides and Z-enol esters provides chiral, alpha-functionalized aldehydes with high selectivity and atom economy. Rh-bisdiazaphospholane catalysts enable hydroformylation of these challenging disubstituted substrates under mild reaction conditions and low catalyst loadings. The synthesis of a protected analog of l-DOPA demonstrates the utility of AHF for enantioselective, atom-efficient synthesis of peptide precursors.
- Abrams, M. Leigh,Foarta, Floriana,Landis, Clark R.
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supporting information
p. 14583 - 14588
(2015/01/08)
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- Nickel(II)-magnesium-catalyzed cross-coupling of 1,1-dibromo-1-alkenes with diphenylphosphine oxide: One-pot synthesis of (E)-1-alkenylphosphine oxides or bisphosphine oxides
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A novel nickel(II)-magnesium-mediated cross-coupling of diphenylphosphine oxide with a variety of 1,1-dibromo-1-alkenes has been developed, which provides a powerful and general methodology for the stereoselective synthesis of various (E)-1-alkenylphosphine oxides or bisphosphine oxides, with operational simplicity of the procedure, good to high yields and broad substrate applicability. Mechanistic studies reveal that the reaction might involve a Hirao reduction, cross-coupling and Michael addition. Copyright
- Liu, Liu,Wang, Yulei,Zeng, Zhiping,Xu, Pengxiang,Gao, Yuxing,Yin, Yingwu,Zhao, Yufen
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supporting information
p. 659 - 666
(2013/04/10)
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- Enantioselective syntheses and X-ray structures of (S)- and (R)-N-norlaudanidine: trace opium constituents
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The enantioselective synthesis of each of the enantiomers of N-norlaudanidine, a minor Papaver somniferum opium benzyltetrahydoisoquinoline alkaloid is described. This was achieved using a chiral auxiliary-mediated Bischler-Napieralski cyclization-sodium borohydride reduction strategy. The X-ray crystal structures of each of these secondary amines are reported.
- Zein, Ahmed L.,Dakhil, Otman O.,Dawe, Louise N.,Georghiou, Paris E.
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scheme or table
p. 177 - 180
(2010/03/04)
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- Enantioselective total synthesis and X-ray structures of the tetrahydroprotoberberine alkaloids (-)-(S)-tetrahydropalmatrubine and (-)-(S)-corytenchine
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Enantioselective total syntheses and X-ray structures of both (S)-tetrahydropalmatrubine (2) and (S)-corytenchine (3) are reported for the first time. They were both derived from (S)-N-norlaudanidine, a benzyltetrahydroisoquinoline that was synthesized with high (>95% ee) enantioselectivity using a chiral auxiliary-assisted Bischler-Napieralski cyclization/reduction approach.
- Zein, Ahmed L.,Dawe, Louise N.,Georghiou, Paris E.
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scheme or table
p. 1427 - 1430
(2010/10/21)
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- Pd-catalyzed domino synthesis of internal alkynes using triarylbismuths as multicoupling organometallic nucleophiles
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Figure presented The domino coupling reaction of 1,1-dibromo-1-alkenes with triarylbismuth nucleophiles has been demonstrated to furnish disubstituted alkynes directly under catalytic palladium conditions. The couplings of triarylbismuths as multicoupling nucleophiles with 3 equiv of 1,1-dibromo-1-alkenes are very fast, affording high yields of alkynes in a short reaction time. Thus, an efficient domino process has been accomplished using 1,1-dibromo-1-alkenes as surrogates for internal alkyne synthesis in couplings with triarylbismuths in a one-pot operation.
- Rao, Maddali L. N.,Jadhav, Deepak N.,Dasgupta, Priyabrata
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supporting information; experimental part
p. 2048 - 2051
(2010/07/03)
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- 1,1-dibromo-1-alkenes as valuable partners in the copper-catalyzed direct alkynylation of azoles
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The copper-catalyzed direct alkynylation of azoles with 1,1-dibromo-1-alkenes as electrophiles is described. These easily accessible substrates are a useful addition to the field of direct alkynylations in an efficient and functional group tolerant reaction to provide a straightforward entry to diverse alkynyl heterocycles.
- Pacheco Berciano, Beatriz,Lebrequier, Sabrina,Besselievre, Francois,Piguel, Sandrine
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supporting information; experimental part
p. 4038 - 4041
(2010/11/16)
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- Functionalization of Csp3-H bond-Sc(OTf)3-catalyzed domino 1,5-hydride shift/cyclization/Friedel-Crafts acylation reaction of benzylidene Meldrum's acids
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Under Sc(OTf)3 catalysis, benzylidene Meldrum's acids bearing a tethered p-methoxyphenethyl group were observed to undergo a [1,5]-hydride shift/cyclization at room temperature, representing a mild Csp3-H bond functionalization. The resulting spiro Meldrum's acid intermediates then underwent intramolecular Friedel-Crafts acylation, completing the one-pot, domino reaction. The reported protocol generates the 6-6-5-6 tetracyclic core of tetrahydrobenzo[b]fluoren-11-ones.
- Mahoney, Stuart J.,Moon, David T.,Hollinger, Jon,Fillion, Eric
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supporting information; experimental part
p. 4706 - 4709
(2011/03/18)
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- Stereoselective synthesis of 3,3-diarylacrylonitriles as tubulin polymerization inhibitors
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(Chemical Equation Presented) A series of 3,3-diarylacrylonitriles were synthesized stereo-selectively as tubulin polymerization inhibitors for potential use in cancer chemotherapy. This synthetic route features stannylcupration and palladium-catalyzed St
- Fang, Zhenglai,Song, Yunlong,Sarkar, Taradas,Hamel, Ernest,Fogler, William E.,Agoston, Gregory E.,Fanwick, Phillip E.,Cushman, Mark
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p. 4241 - 4244
(2008/09/20)
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- Novel 3-Thia-10-Aza-Phenanthrene Derivatives
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The compounds of formula I in which A, R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
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Page/Page column 18
(2008/06/13)
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- Novel 3-Oxa-10-Aza-Phenanthrenes
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The compounds of formula I in which R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
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Page/Page column 15-16
(2010/11/28)
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- Synthesis of tetrahydropyran-4-ones and thiopyran-4-ones from donor-substituted α-bromostyrene derivatives
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Tetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with a 3-aryl substituent were synthesized by double-conjugate addition of water or H2S to divinyl ketones. These starting materials were prepared in two steps by conversion of lit
- Rosiak, Anna,Frey, Wolfgang,Christoffers, Jens
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p. 4044 - 4054
(2007/10/03)
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- Rapid synthesis of triazole-modified resveratrol analogues via click chemistry
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Resveratrol is a phytoalexin able to display an array of biological activities. We decided to replace the double bond with a triazole ring using the archetypical click reaction: the Huisgen [3 + 2] cycloaddition. Seventy-two triazole derivatives were synt
- Pagliai, Francesca,Pirali, Tracey,Del Grosso, Erika,Di Brisco, Riccardo,Tron, Gian Cesare,Sorba, Giovanni,Genazzani, Armando A.
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p. 467 - 470
(2007/10/03)
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- Total synthesis of (+)-lithospermic acid by asymmetric intramolecular alkylation via catalytic C-H bond activation
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The total synthesis of (+)-lithospermic acid is described. The efficient synthesis features an asymmetric alkylation via C-H bond activation to assemble the dihydrobenzofuran core of the natural product. This was accomplished via a chiral imine-directed C
- O'Malley, Steven J.,Tan, Kian L.,Watzke, Anja,Bergman, Robert G.,Ellman, Jonathan A.
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p. 13496 - 13497
(2007/10/03)
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- 3α-Hydroxy-3β-(phenylethynyl)-5β-pregnan-20-ones: Synthesis and pharmacological activity of neuroactive steroids with high affinity for GABA(A) receptors
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Neuroactive steroids that allosterically modulate GABA(A) receptors have potential uses as anticonvulsants, anxiolytics, and sedative-hypnotic agents. Recently, a series of pregnanes substituted with simple alkyl groups at the 3β-position were synthesized
- Upasani, Ravindra B.,Yang, Kevin C.,Acosta-Burruel, Manuel,Konkoy, Chris S.,McLellan, James A.,Woodward, Richard M.,Lan, Nancy C.,Carter, Richard B.,Hawkinson, Jon E.
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- Approaches to 2,6-Diaryl-3,7-DioxabicycloOctane Lignans via Asymmetric Synthesis of Dihydro- and Tetrahydro-furan Derivatives
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Cyclisation of chiral non-racemic phenylsulphonylvinyl epoxy ethers, produced using the Sharpless epoxidation reaction, has been used to prepare a series of enantiomerically enriched 2-aryl-4-(α-hydroxybenzyl)-4,5-dihydrofuran derivatives.Reduction of these compounds using triethylsilane and BF3-diethyl ether gave the corresponding tetrahydrofuran derivatives stereoselectively.Attempts to convert either the dihydro- or tetrahydro-furan derivatives into lignans belonging to the 2,6-diaryl-3,7-dioxabicyclooctane series so far proved unsuccessful.
- Pelter, Andrew,Ward, Robert S.,Little, Gillian M.
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p. 2775 - 2790
(2007/10/02)
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