- Facile and divergent optimization of chromazonarol enabled the identification of simplified drimane meroterpenoids as novel pharmaceutical leads
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The diversity of drimane hydroquinones was significantly expanded by the facile construction of (+)-chromazonarol relevant natural products, isomers, and analogues for the discovery of new pharmaceutical leads. The structure-activity relationship of (+)-c
- Hu, Nvdan,Kong, Wenlong,Li, Shengkun,Song, Baoan,Wang, Xia
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supporting information
(2021/10/16)
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- α-Lithiobenzyloxy as a Directed Metalation Group in ortho-Lithiation Reactions
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The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila(germa)dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
- Sedano, Carlos,Velasco, Rocío,Feberero, Claudia,Suárez-Pantiga, Samuel,Sanz, Roberto
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supporting information
p. 6365 - 6369
(2020/08/24)
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- Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
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By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
- Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
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supporting information
p. 15058 - 15068
(2016/10/11)
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- Synthesis of lamellarin U and lamellarin G trimethyl ether by alkylation of a deprotonated α-aminonitrile
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(Chemical Equation Presented) 1,2,3,4-Tetrahydroisoquinoline-1- carbonitriles can serve as starting materials for the one-pot synthesis of 5,6-dihydropyrrolo[2,1a]isoquinolines and 1-benzyl-3,4-dihydroisoquinolines. The latter compounds were transformed to lamellarin G trimethyl ether and lamellarin U in short reaction sequences. This method allows the introduction of acid-sensitive protecting groups for the phenolic hydroxy functions which would be cleaved under the harsh conditions of the classical Bischler-Napieralski reaction.
- Liermann, Johannes C.,Opatz, Till
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p. 4526 - 4531
(2008/09/21)
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- Convenient synthetic route to a dehydrorotenoid via selective intramolecular aldol condensation of 1,2-diaryl diketone
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Synthesis of dehydrorotenoid (1) was successfully achieved via an intramolecular aldol reaction of the corresponding 1,2-diaryl diketone intermediate. The 1,2-diaryl diketone was prepared using a ruthenium-catalyzed oxidation of the corresponding substituted diaryl acetylene. Treatment of this 1,2-diketone with l-proline induced a selective intramolecular aldol condensation reaction, forming the desired benzopyranone over the alternative benzofuran. Deprotection, cyclization, and dehydration gave the target compound in good overall yield.
- Tummatorn, Jumreang,Khorphueng, Prapas,Petsom, Amorn,Muangsin, Nongnuch,Chaichit, Narongsak,Roengsumran, Sophon
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p. 11878 - 11885
(2008/03/13)
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- Studies toward the total synthesis of angelmicin B (hibarimicin B): Synthesis of a model CD-D′ arylnaphthoquinone
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(Chemical Equation Presented) A synthesis of arylnaphthoquinone 22 corresponding to the CD-D′ unit of angelmicin B via the Suzuki coupling of the D′ arylboronic acid 15 with the CD bromonaphthoquinone 21 is described. The mild conditions for the Suzuki cross-coupling leading to 22 may prove to be useful for the eventual late-stage coupling of the two highly functionalized halves of angelmicin B.
- Narayan, Sridhar,Roush, William R.
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p. 3789 - 3792
(2007/10/03)
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- The Structure of Thalibrunine, a Reinvestigation and Revision
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Evidence is presented that thalibrunine has structure 2 and is the 2'-hydroxy derivative of hernandezine.Ceric ammonium nitrate oxidation of thalibrunine acetate (3) gave 2-methoxy-4-acetoxy-4',5-diformyldiphenyl ether (6), which was also prepared synthet
- Wu, Jinn,Beal, Jack L.,Doskotch, Raymond W.
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p. 208 - 212
(2007/10/02)
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