- Contra-Thermodynamic Positional Isomerization of Olefins
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A light-driven method for the contra-thermodynamic positional isomerization of olefins is described. In this work, stepwise PCET activation of a more substituted and more thermodynamically stable olefin substrate is mediated by an excited-state oxidant an
- Zhao, Kuo,Knowles, Robert R.
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supporting information
p. 137 - 144
(2022/01/19)
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- Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron-Rich Substrates
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Fluorinated alkyl groups are important motifs in bioactive compounds, positively influencing pharmacokinetics, potency and conformation. The oxidative difluorination of alkenes represents an important strategy for their preparation, yet current methods are limited in their alkene-types and tolerance of electron-rich, readily oxidized functionalities, as well as in their safety and scalability. Herein, we report a method for the difluorination of a number of unactivated alkene-types that is tolerant of electron-rich functionality, giving products that are otherwise unattainable. Key to success is the electrochemical generation of a hypervalent iodine mediator using an “ex-cell” approach, which avoids oxidative substrate decomposition. The more sustainable conditions give good to excellent yields in up to decagram scales.
- Doobary, Sayad,Sedikides, Alexi T.,Caldora, Henry P.,Poole, Darren L.,Lennox, Alastair J. J.
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supporting information
p. 1155 - 1160
(2019/12/11)
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- Synthesis of Piperidine Derivatives by Rhodium- Catalyzed Tandem Reaction of N-Sulfonyl-1,2,3-Triazole and Vinyl Ether
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A chemoselective tandem reaction of 4-acyloxymethylene-1-sulfonyl-1,2,3-triazole and vinyl ether was reported, producing polysubstituted piperidine derivatives in up to 96% yield. The key intermediate N-sulfonyl 1-azadiene generated by migration of the OAc group to the α-imino rhodium carbene was isolated and a plausible mechanism was proposed. Several related ring systems were constructed from the highly functionalized products. (Figure presented.).
- Yu, Sisi,An, Yuehui,Wang, Wenlin,Xu, Ze-Feng,Li, Chuan-Ying
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supporting information
p. 2125 - 2130
(2018/04/17)
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- Decarboxylative alkenylation
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Olefin chemistry, through pericyclic reactions, polymerizations, oxidations, or reductions, has an essential role in the manipulation of organic matter. Despite its importance, olefin synthesis still relies largely on chemistry introduced more than three decades ago, with metathesis being the most recent addition. Here we describe a simple method of accessing olefins with any substitution pattern or geometry from one of the most ubiquitous and variegated building blocks of chemistry: alkyl carboxylic acids. The activating principles used in amide-bond synthesis can therefore be used, with nickel- or iron-based catalysis, to extract carbon dioxide from a carboxylic acid and economically replace it with an organozinc-derived olefin on a molar scale. We prepare more than 60 olefins across a range of substrate classes, and the ability to simplify retrosynthetic analysis is exemplified with the preparation of 16 different natural products across 10 different families.
- Edwards, Jacob T.,Merchant, Rohan R.,McClymont, Kyle S.,Knouse, Kyle W.,Qin, Tian,Malins, Lara R.,Vokits, Benjamin,Shaw, Scott A.,Bao, Deng-Hui,Wei, Fu-Liang,Zhou, Ting,Eastgate, Martin D.,Baran, Phil S.
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p. 213 - 218
(2017/05/19)
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- Hydroheteroarylation of Unactivated Alkenes Using N-Methoxyheteroarenium Salts
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We report the first reductive coupling of unactivated alkenes with N-methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts under hydrogen atom transfer (HAT) conditions, and an expanded scope for the coupling of alkenes with N-methoxy pyridinium salts. N-Methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts are accessible in 1-2 steps from the commercial arenes or arene N-oxides (25-99%). N-Methoxy imidazolium salts are accessible in three steps from commercial amines (50-85%). In total 36 discrete methoxyheteroarenium salts bearing electron-donating, electron-withdrawing, alkyl, aryl, halogen, and haloalkyl substituents were prepared (several in multigram quantities) and coupled with 38 different alkenes. The transformations proceed under neutral conditions at ambient temperature, provide monoalkylation products exclusively, and form a single alkene addition regioisomer. Preparatively useful and complementary site selectivities in the addition of secondary and tertiary radicals to pyidinium salts are documented: harder secondary radicals favor C-2 addition (2->10:1), while softer tertiary radicals favor bond formation to C-4 (4.7->29:1). A diene possessing a 1,2-disubstituted and 2,2-disubstituted alkene undergoes hydropyridylation at the latter exclusively (61%) suggesting useful site selectivities can be obtained in polyene substrates. The methoxypyridinium salts can also be employed in dehydrogenative arylation, borono-Minisci, and tandem arylation processes. Mechanistic studies support the involvement of a radical process.
- Ma, Xiaoshen,Dang, Hester,Rose, John A.,Rablen, Paul,Herzon, Seth B.
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supporting information
p. 5998 - 6007
(2017/05/04)
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- Brook Rearrangement as Trigger for Carbene Generation: Synthesis of Stereodefined and Fully Substituted Cyclobutenes
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Through a sequence that can be performed in a single vessel, involving regio- and diastereoselective copper-catalyzed carbomagnesiation of cyclopropenes, reaction with acylsilanes, and addition of THF as cosolvent, Brook rearrangement can be triggered to furnish a wide range of cyclobutenes with exceptional diastereoselectivity. Accordingly, stereodefined and highly substituted cyclobutenes with contiguous quaternary carbon centers can be synthesized easily and in high yield. The new strategy constitutes an unprecedented application of Brook rearrangement, one which involves the intermediacy of carbene species.
- Zhang, Fa-Guang,Marek, Ilan
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supporting information
p. 8364 - 8370
(2017/06/28)
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- HETEROARYL COMPOUNDS AS IRAK INHIBITORS AND USES THEREOF
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The present invention relates to compounds of Formula (I) and pharmaceutically acceptable compositions thereof, useful as IRAK inhibitors.
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Paragraph 00191
(2017/05/02)
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- 4 -SUBSTITUTED BENZOXABOROLE COMPOUNDS AND USES THEREOF
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Substituted benzoxaboroles whose structure comprises Formula (III), wherein R3 is selected from –CH3, –CH2CH3, –CH2=CH2, –CH2CH2CH3, –CH(CH3)sub
- -
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Paragraph 00232
(2016/09/22)
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- TRICYCLIC BENZOXABOROLE COMPOUNDS AND USES THEREOF
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Compounds of Formula II wherein X is selected from chloro, fluoro, bromo and iodo, R1 and R2 are each independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3, or -CH(CH3)2
- -
-
Paragraph 00258-00259
(2015/02/25)
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- Repairing the thiol-ene coupling reaction
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Thiol-ene coupling (TEC) reactions emerged as one of the most useful processes for coupling different molecular units under reaction mild conditions. However, TEC reactions involving weak C-H bonds (allylic and benzylic fragments) are difficult to run and often low yielding. Mechanistic studies demonstrate that hydrogen-atom transfer processes at allylic and benzylic positions are responsible for the lack of efficiency of the radical-chain process. These competing reactions cannot be prevented, but reported herein is a method to repair the chain process by running the reaction in the presence of triethylborane and catechol. Under these reaction conditions, a unique repair mechanism leads to an efficient chain reaction, which is demonstrated with a broad range of anomeric O-allyl sugar derivatives including mono-, di-, and tetrasaccharides bearing various functionalities and protecting groups. In good repair: Undesired hydrogen-atom transfers are responsible for the lack of efficiency in thiol-ene coupling reactions involving allyl glycosides. This competing reaction cannot be prevented but can be very efficiently repaired by carrying out the reaction in the presence of triethylborane and catechol.
- Povie, Guillaume,Tran, Anh-Tuan,Bonnaffe, David,Habegger, Jacqueline,Hu, Zhaoyu,Le Narvor, Christine,Renaud, Philippe
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supporting information
p. 3894 - 3898
(2014/05/06)
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- One-pot method for regioselective bromination and sequential carbon-carbon bond-forming reactions of allylic alcohol derivatives
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An efficient one-pot method for the regioselective bromination of allylic alcohol derivatives (two-step reaction sequence) followed by Sonogashira, Negishi, or Suzuki-Miyaura coupling reactions in the same reaction vessel (three-step reaction sequence) ha
- Kutsumura, Noriki,Matsubara, Yusuke,Niwa, Kentaro,Ito, Ai,Saito, Takao
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p. 3337 - 3346
(2013/06/27)
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- COMPOUNDS
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The present invention features compounds of formula (I): and salts thereof, pharmaceutical compositions comprising said compounds, and uses of such compounds in treating or preventing viral infections, such as HCV infections, and diseases associated with such infections.
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Page/Page column 57
(2012/06/01)
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- Enantiocomplementary chemoenzymatic asymmetric synthesis of (R)- And (S)-chromanemethanol
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A non-lipase-based, enantiocomplementary chemoenzymatic route towards enantiopure (R)- and (S)-chromane-methanol (12), which are the key building blocks for the synthesis of stereoisomerically pure α-tocopherols, has been achieved by the biocatalytic reso
- Fuchs, Michael,Simeo, Yolanda,Ueberbacher, Barbara T.,Mautner, Barbara,Netscher, Thomas,Faber, Kurt
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experimental part
p. 833 - 840
(2009/07/05)
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- Encapsulated molecular catalysts in polysiloxane gels: Ruthenium cluster-catalyzed isomerization of alkenes
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Novel ruthenium-encapsulating polysiloxane gels are prepared by treatment of polymethylhydrosiloxane with diols in the presence of (μ3, η2,η3,η5-acenaphthylene)Ru 3(CO)7, and act as reusable catalysts in the isomerization of alkenes without leakage of the catalyst species. The Royal Society of Chemistry.
- Motoyama, Yukihiro,Abe, Motonori,Kamo, Kazuyuki,Kosako, Yusuke,Nagashima, Hideo
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supporting information; experimental part
p. 5321 - 5323
(2009/03/11)
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- Bacillus subtilis epoxide hydrolase-catalyzed preparation of enantiopure 2-methylpropane-1,2,3-triol monobenzyl ether and its application to expeditious synthesis of (R)-bicalutamide
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Expeditious synthesis of (R)-bicalutamide (1), a synthetic antiandrogen, from enantiopure 2-methylpropane-1,2,3-triol monobenzyl ether (4) was achieved. An engineered Bacillus subtilis epoxide hydrolase worked enantioselectively on the racemic epoxide (7) to provide the above starting material in highly enantiomerically enriched state.
- Fujino, Aya,Asano, Masayoshi,Yamaguchi, Hitomi,Shirasaka, Naoki,Sakoda, Akiko,Ikunaka, Masaya,Obata, Rika,Nishiyama, Shigeru,Sugai, Takeshi
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p. 979 - 983
(2008/02/04)
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- Enantioselective synthesis of cyclic ethers through a vanadium-catalyzed resolution/oxidative cyclization
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(Chemical Equation Presented) Two steps, one catalyst: A vanadium(v)-oxo complex with a tridentate Schiff base as an additional ligand catalyzes the title reaction which transforms racemic bishomoallylic α-hydroxyesters into trans-tetrahydropyrans (THPs)
- Blanc, Aurelien,Toste, F. Dean
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p. 2096 - 2099
(2007/10/03)
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- Hydrazines and azides via the metal-catalyzed hydrohydrazination and hydroazidation of olefins
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The discovery, study, and implementation of the Co- and Mn-catalyzed hydrohydrazination and hydroazidation reactions of olefins are reported. These reactions are equivalent to direct hydroaminations of C-C double bonds with protected hydrazines or hydrazoic acid but are based on a different concept in which the H and the N atoms come from two different reagents, a silane and an oxidizing nitrogen source (azodicarboxylate or sulfonyl azide). The hydrohydrazination reaction using di-tert-butyl azodicarboxylate is characterized by its ease of use, large functional group tolerance, and broad scope, including mono-, di-, tri-, and tetrasubstituted olefins. Key to the development of the hydroazidation reaction was the use of sulfonyl azides as nitrogen sources and the activating effect of tert-butyl hydroperoxide. The reaction was found to be efficient for the functionalization of mono-, di-, and trisubstituted olefins, and only a few functional groups are not tolerated. The alkyl azides obtained are versatile intermediates and can be transformed to the free amines or triazoles without isolation of the azides. Preliminary mechanistic investigations suggest a rate-limiting hydrocobaltation of the alkene, followed by an amination reaction. Radical intermediates cannot be ruled out and may be involved.
- Waser, Jerome,Gaspar, Boris,Nambu, Hisanori,Carreira, Erick M.
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p. 11693 - 11712
(2007/10/03)
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- Intra- and intermolecular 1,3-dipolar cycloaddition of sugar ketonitrones with mono-, di-, and trisubstituted dipolarophiles
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The 1,3-dipolar cycloaddition of sugar ketonitrones is a useful synthetic procedure to build up nitrogenated quaternary centers in terms of scope (substrate, dipolarophile, inter- and intramolecular versions), yield, and regio- and stereoselectivity. The
- Torrente, Susana,Noya, Beatriz,Branchadell, Vicenc,Alonso, Ricardo
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p. 4772 - 4783
(2007/10/03)
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- Tandem hydroformylation/Fischer indole synthesis: A novel and convenient approach to indoles from olefins
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(Matrix presented) A novel one-pot synthesis of indole systems via tandem hydroformylation/Fischer indole synthesis starting from olefins and arylhydrazines is described. This tandem procedure leads directly to 3-substituted indoles if unsubstituted phenylhydrazine is used and to 3,5- respectively 3,7-disubstituted indoles if para- or ortho-substituted arylhydrazines are used.
- Koehling, Petra,Schmidt, Axel M.,Eilbracht, Peter
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p. 3213 - 3216
(2007/10/03)
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- Chemo-enzymatic enantioconvergent synthesis of C4-building blocks containing a fully substituted chiral carbon center using bacterial epoxide hydrolases
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A highly efficient chemo-enzymatic asymmetric synthesis of chiral C4-building blocks containing a fully substituted carbon center is reported. The key transformation consists of a deracemization based on an enantioconvergent asymmetric hydrolys
- Steinreiber,Hellstr?m,Mayer,Orru,Faber
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p. 111 - 113
(2007/10/03)
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- Preparation of chiral building blocks for a highly convergent vitamin E synthesis. Systematic investigations on the enantioselectivity of the sharpless bishydroxylation
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The enantioselective bishydroxylation of protected 2-methylprop-2-enol 15 and 3-methylbut-3-en-1-ol 16 to give the corresponding diols 18 and 19, respectively, which can be transformed into building blocks for the synthesis of natural vitamin E, is described. It is shown that the enantioselectivity of the bishydroxylation reaction clearly depends on the type of protecting group and its distance from the alkene moiety, with 96% ee for 16a and 16f as the best and 8% ee for 15d as the lowest result.
- Tietze, Lutz F.,Goerlitzer, Jochen
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p. 873 - 878
(2007/10/03)
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- REACTIONS OF PHOSPHORUS PENTACHLORIDE WITH ALLYL ARYL ETHERS, SULFIDES, AND NAPHTHALENE DERIVATIVES
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Conditions for phosphorylation of allyl aryl and aryl methylallyl ethers and sulfides, as well as alkenyl- and alkoxynaphthalenes, have been developed.
- Anisimova, E. A.,Mitrasov, Yu. N.,Kormachev, V. V.
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p. 356 - 360
(2007/10/03)
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- 3(1-hydoxyethyl)azetidinone compounds and their production
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An amino acid compound of the formula: STR1 wherein R is a lower alkyl group, R1 is a hydrogen atom or a protecting group for carboxyl, R2 is a hydrogen atom, a protecting group for amino, an optionally substituted allyl group of the formula: STR2 (wherein R3 and R4 are each a hydrogen atom, a lower alkyl group or an aryl group), a beta-hydroxyethyl group in which the hydroxyl group is optionally protected, a formylmethyl group in which the formyl group is optionally protected, a carboxymethyl group in which the carboxyl group is protected or a 2-furylmethyl group and X is an optionally protected carboxyl group, a hydroxymethyl group in which the hydroxyl group is optionally protected or a substituted mercaptomethyl group of the formula: (wherein R5 is an aryl group or an ar(lower)alkyl group), which is a useful intermediate in the synthesis of 1-alkylcarbapenem compounds.
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- Study of ketene-alkene cycloadditions and cycloreversions of cyclobutanones
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A study of the addition reaction of tert-butylcyanoketene (TBCK) with several alkenes and thermal cycloreversion of various TBCK-alkene adducts in different solvents has been carried out. Cycloreversions were usually found to follow a concerted pathway.
- Al-Husaini,Muqtar,Ali Sk.
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p. 7719 - 7726
(2007/10/02)
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- The 3,4-Dihydro-2H-pyran Approach to (+)-Milbemycin β3. Part 2. An Improved Synthesis of (2R,4S,6S,8R,9S)-2--8,9-dimethyl-4-(dimethyl-t-butylsilyloxy)-1,7-dioxaspiroundecane
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A more efficient synthesis of the title compound (2), previously used in a total synthesis of (+)-milbemycin β3 (1), is described.The key step in the sequence involves a nucleophilic cleavage of the oxirane (4) by the organocuprate derived from
- Kocienski, Philip J.,Street, Stephen D. A.,Yeates, Clive,Campbell, Simon F.
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p. 2189 - 2194
(2007/10/02)
-
- STUDIES IN MACROLIDE SYNTHESIS: AN EFFICIENT SYNTHESIS OF TWO CHIRAL FRAGMENTS OF ERYTHRONOLIDE A
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An efficient asymmetric synthesis of the C1-C5 fragment (3) together with the epimeric C7-C11 fragment (4) used in the Stork approach to the synthesis of erythronolide A is described.
- Paterson, Ian,Patel, Shailesh K.,Porter, John R.
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p. 3395 - 3396
(2007/10/02)
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