- Diversification of Peptidomimetics and Oligopeptides through Microwave-Assisted Rhodium(III)-Catalyzed Intramolecular Annulation
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A chemoselective rhodium(III)-catalyzed cascade annulation for the construction of the indolizinone and quinolizinone scaffolds is developed. Diversification of peptidomimetics and oligopeptides is achieved in a rapid and step-economical manner through the combination of Ugi reaction and microwave-assisted rhodium(III)-catalyzed intramolecular annulation via C(sp2)-H activation without installing a directing group. (Figure presented.).
- Song, Liangliang,Tian, Guilong,Blanpain, Anna,Van Meervelt, Luc,Van der Eycken, Erik V.
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- Palladium-Catalyzed Aminomethylative Oppolzer-Type Cyclization of Enynes: Access to Aminomethylated Benzofulvenes
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A novel palladium-catalyzed Oppolzer-type cyclization reaction aided by the aminomethyl cyclopalladated complex has been developed, which provides rapid access to functionalized benzofulvenes with excellent stereoselectivity. The corresponding products can undergo Diels–Alder reaction with maleimides, providing a series of complex polycyclic compounds with excellent regio- and stereoselectivities.
- Huang, Hanmin,Huang, Renbin,Li, Renren,Yu, Bangkui
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supporting information
p. 9510 - 9515
(2021/12/14)
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- Carbonyl-Directed Addition of N-Alkylhydroxylamines to Unactivated Alkynes: Regio- and Stereoselective Synthesis of Ketonitrones
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A variety of ketonitrones were synthesized in moderate to excellent yields with high chemo-, regio-, and stereoselectivity by using carbonyl-directed addition of N-alkylhydroxylamines to unactivated alkynes under mild conditions. The product diverisity could be controlled by the use of different bases, and EtN(n-Pr)2 could promote the formation of ketonitrones while using EtONa as base led to indanone-derived nitrones. Control experiments indicated that the carbonyl group of the substrate acted as an H-bond acceptor except for an electron-withdrawing group, and conjugated enone skeleton accounted for the high selectivity.
- Liu, Yilin,Feng, Xiangqing,Liu, Yanyun,Lin, Hongwei,Li, Yuanxiang,Gong, Yingying,Cao, Lei,Chen, Liping
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p. 382 - 386
(2019/01/11)
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- Visible-Light-Promoted Generation of α-Ketoradicals from Vinyl-bromides and Molecular Oxygen: Synthesis of Indenones and Dihydroindeno[1,2-c]chromenes
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Ortho-alkynylated α-bromocinnamates can be converted by a visible-light-mediated photocascade reaction with molecular oxygen into either indenones or dihydroindeno[1,2-c]chromenes. The one-step process features key photochemical steps, that is, the initial activation of vinyl bromides through energy transfer to give α-ketoradicals in a reaction with molecular oxygen, followed by α-oxidation of an arene moiety by 6-π electrocyclization, and subsequent hydroxylation by an electron-transfer process from the same photocatalyst leads to the dihydroindeno[1,2-c]chromenes.
- Pagire, Santosh K.,Kreitmeier, Peter,Reiser, Oliver
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p. 10928 - 10932
(2017/08/30)
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- Drawing from a pool of radicals for the design of selective enyne cyclizations
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Despite the possibility of intermolecular attack at four different locations, the Bu3Sn-mediated radical cyclization of aromatic enynes is surprisingly selective. The observed reaction path originates from the least stable of the equilibrating pool of isomeric radicals produced by intermolecular Bu3Sn attack at the π-bonds of substrates. The radical pool components are kinetically self-sorted via 5-exo-trig closure, the fastest of the four possible cyclizations. The resulting Sn-substituted indenes are capable of further transformations in reactions with electrophiles.
- Mondal, Sayantan,Mohamed, Rana K.,Manoharan, Mariappan,Phan, Hoa,Alabugin, Igor V.
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supporting information
p. 5650 - 5653
(2013/12/04)
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- Domino hydroarylation-cyclization reaction: One-pot synthesis of indane-fused 3,4-dihydrocoumarins
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A tin(II) triflate-catalyzed domino hydroarylation-cyclization reaction has been developed to access a wide-variety of methyleneindane-fused 3,4-hydrocoumarins. A judiciously selected bi-functional Lewis acidic catalyst has been successfully applied to promote two ring-closing events as a single-pot operation.
- Joo, Jin Hyuck,Youn, So Won
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p. 559 - 568
(2013/05/09)
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- Regio- and stereoselective construction of highly functionalized 3-benzazepine skeletons through ring-opening cycloamination reactions catalyzed by Gold
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Ring size under control: Highly functionalized 1-amino- or 1-hydroxy-1H-benzo[d]azepines have been prepared through a gold-catalyzed cyclization of (o-alkynyl)phenyl aziridines with heteronucleophiles. After removal of the phthalimido group, the products can be further transformed into 1H-benzo[d]azepin-1-ones (see scheme; IBX=2-iodoxybenzoic acid, Phth=pthalimido).
- Du, Xiangwei,Yang, Shuang,Yang, Jingyu,Liu, Yuanhong
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p. 4981 - 4985
(2011/06/17)
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- Synthetic applications of o- and p-halobenzyl sulfones as zwitterionic synthons: Preparation of Ortho-substituted cinnamates and biarylacetic acids
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The synthetic applications of o-halobenzyl and p-halobenzyl sulfones as precursors of 1,3- and 1,5-zwitterionic synthons, respectively, are described. Their α-sulfonyl carbanions, generated by means of the phosphazene base P2-Et or BuLi or K2CO3 under PTC conditions, reacted with different electrophiles such as alkyl halides, aldehydes, and electrophilic olefins. Palladium-catalyzed cross-coupling processes such as Heck, Suzuki, and Sonogashira reactions can be efficiently performed at the halogen atom. These two sequential functionalization processes are applied to the synthesis of ortho-substituted cinnamates and pharmaceuticals belonging to the family of p-biarylacetic acids such as 4-biphenylacetic acid, namoxyrate, xenyhexenic acid, and biphenylpropionic acid.
- Costa, Ana,Najera, Carmen,Sansano, Jose M.
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p. 5216 - 5225
(2007/10/03)
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- P2-Et-mediated deprotonation of ortho-halobenzyl sulfones: Synthetic applications as zwitterionic synthons
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α-Sulfonyl benzylic carbanions, derived from ortho-halobenzyl sulfones 5 (Hal = Br, I), can be easily generated by the phosphazene base P2-Et and react with different electrophiles such as alkyl halides, aldehydes and ethyl acrylate. Palladium
- Costa,Nájera,Sansano
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p. 1881 - 1884
(2007/10/03)
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