- Di- and tetrahydropyrans with orthogonally protected hydroxymethyl side chains: A synthetic route and the structure elucidation of an unexpected acetal cleavage product
-
A synthesis of dihydropyrans with orthogonally protected hydroxymethyl side chains is presented in this contribution. Key steps of the synthesis are the regioselective epoxide opening using vinyl cuprate reagents, selective protection of primary alcohols
- Schmidt, Bernd,Pohler, Michael,Costisella, Burkhard
-
-
Read Online
- Total Synthesis and Structural Assignment of (?)-Fusaequisin A
-
(?)-Fusaequisin A is an irregularly assembled polyketide isolated from the ascomycete Fusarium equiseti. Fusaequisin A shares a carbon backbone with curvicollide C from the ascomycete Podospora curvicolla but its absolute configuration remained hitherto u
- Schmidt, Ann-Christin,Hiersemann, Martin
-
supporting information
(2021/12/14)
-
- Design, Synthesis, and Activity Evaluation of Novel Acyclic Nucleosides as Potential Anticancer Agents in Vitro and in Vivo
-
In the present work, 103 novel acyclic nucleosides were designed, synthesized, and evaluated for their anticancer activities in vitro and in vivo. The structure-activity relationship (SAR) studies revealed that most target compounds inhibited the growth of colon cancer cells in vitro, of which 3-(6-chloro-9H-purin-9-yl)dodecan-1-ol (9b) exhibited the most potent effect against the HCT-116 and SW480 cells with IC50 values of 0.89 and 1.15 μM, respectively. Furthermore, all of the (R)-configured acyclic nucleoside derivatives displayed more potent anticancer activity compared to their (S)-counterparts. Mechanistic studies revealed that compound 9b triggered apoptosis in the cancer cell lines via depolarization of the mitochondrial membrane and effectively inhibited colony formation. Importantly, compound 9b inhibited the growth of the SW480 xenograft in a mouse model with low systemic toxicity. These results indicated that acyclic nucleoside compounds are viable as potent and effective anticancer agents, and compound 9b may serve as a promising lead compound that merits further attention in future anticancer drug discovery.
- Hao, Er-Jun,Li, Gong-Xin,Liang, Yu-Ru,Xie, Ming-Sheng,Wang, Dong-Chao,Jiang, Xiao-Han,Cheng, Jia-Yi,Shi, Zhi-Xian,Wang, Yang,Guo, Hai-Ming
-
supporting information
p. 2077 - 2109
(2021/02/16)
-
- Iridium-Catalyzed Regioselective Hydroalkynylation of Internal Alkenes Directed by an Oxime
-
We report here an iridium-catalyzed hydroalkynylation of allylic alcohols protected by an oxime group. Catalytic alkynylation occurs exclusively at the distal position of the alkene. This method generates γ-alkynyl alcohol oximes directly from internal alkenes and terminal alkynes. The oxime group can be readily removed to afford a free alcohol, thus providing an indirect route for the catalytic hydroalkynylation of allylic alcohols.
- Gao, Peng-Chao,Li, Bi-Jie,Wang, Zi-Xuan
-
p. 9500 - 9504
(2021/12/14)
-
- Gold-Catalyzed Asymmetric Thioallylation of Propiolates via Charge-Induced Thio-Claisen Rearrangement
-
A gold(I)-catalyzed enantioselective thioallylation of propiolates with allyl sulfides is described. The key mechanistic element is a sulfonium-induced Claisen rearrangement which helps minimize the allyl dissociation and render higher enantioselectivity. This protocol features remarkable scope of the allyl moiety, allowing enantiocontrolled synthesis of all-carbon quaternary centers, and exhibits exceptional functional group compatibility with many Lewis bases and π-bonds. This intermolecular variant of Claisen rearrangement forges both C-S and C-C bonds concomitantly, providing efficient access to interesting optically active organosulfur compounds which can be transformed further through the vinyl sulfide as a functional handle. The rate of the reaction was zeroth order with respect to allyl sulfides, which suggested a reversible inhibition, providing a resting state for the catalyst. The Hammett plot displayed a correlation with σp values, suggesting a turnover-limiting sigmatropic rearrangement where decreased electron-density on sulfur accelerated the rearrangement.
- Kim, Hanbyul,Jang, Jiwon,Shin, Seunghoon
-
supporting information
p. 20788 - 20795
(2020/11/27)
-
- Formal synthesis of borrelidin: A highly enantio- and diastereoselective access to the Morken's C2-C12 intermediate
-
In contrast to methyl and isobutyl phenyl sulfone, condensing under basic conditions higher alkyl sulfones and trans-2,3-epoxy-butanol 13c (or its O-benzyl and O-silyl derivatives) proved unfeasible, a difficulty that was overcome by using mono ethers of trans-2,3-epoxy-butane-1,4-diol 35c as the electrophilic reagents. Thus, adding excess BuLi to a mixture of the benzyl ether 35b and sulfone ent-12a, a stereodiad sulfone prepared in pure state from the R-Roche ester, via the O-trityloxy-sulfone ent-12c (X-ray), gave, after elimination by column chromatography of the side-formed regioisomer, a diolsulfone that was next converted to sulfone 20 by means of conventional functional-group modifications. Reacting like-wise this sulfone with the parent O-PMB derivative 35a, and then proceeding to the same purification process and function adjustment, delivered the title fragment in virtually pure state.
- Gembus, Vincent,Karmazin, Lydia,Uguen, Daniel,Zoller, Thomas
-
supporting information
p. 359 - 380
(2019/02/25)
-
- Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow
-
A copper-based photocatalyst, Cu(tmp)(BINAP)BF4, was found to be active in a photoredox Appel-type conversion of alcohols to bromides. The catalyst was identified from a screening of 50 complexes and promoted the transformation of primary and secondary alcohols to their corresponding bromides and carboxylic acids to their anhydrides. The protocol was also amendable and optimized under continuous flow conditions.
- Minozzi, Clémentine,Grenier-Petel, Jean-Christophe,Parisien-Collette, Shawn,Collins, Shawn K.
-
supporting information
p. 2730 - 2736
(2018/11/21)
-
- Total Synthesis of Ovafolinins A and B: Unique Polycyclic Benzoxepin Lignans through a Cascade Cyclization
-
Ovafolinins A and B, isolated from Lyonia ovalifolia var. elliptica, are lignans that contain a unique bridged structure containing a penta- and tetracyclic benzoxepin and an aryl tetralin. We report the first total synthesis of these natural products in which an acyl-Claisen rearrangement was initially utilized to construct the lignan backbone with correct relative stereochemistry. Judicious use of a bulky protecting group placed reactive moieties in the correct orientation, thereby resulting in a cascade reaction to form the bridged benzoxepin/aryl tetralin from a linear precursor in a single step. Modification of this route allowed the enantioselective synthesis of (+)-ovafolinins A and B, which confirmed the absolute stereochemistry, and comparison of optical rotation suggests that these compounds are found as scalemic mixtures in nature.
- Davidson, Samuel J.,Barker, David
-
supporting information
p. 9483 - 9486
(2017/08/01)
-
- Total synthesis of (-)-bicubebin A, B, (+)-bicubebin C and structural reassignment of (-)-cis-cubebin
-
The first total synthesis of (-)-bicubebin A, and two previously unreported dilignans, (-)-bicubebin B and (+)-bicubebin C has been achieved through the dimerization of (-)-cubebin, confirming the structure and absolute stereochemistry of (-)-bicubebin A. Analysis of the data for (-)-bicubebin B showed it matched that of reported compound (-)-cis-cubebin. The NMR data of the subsequently synthesized proposed structure of cis-cubebin confirmed that its original proposed structure was incorrect.
- Davidson, Samuel J.,Pearce, A. Norrie,Copp, Brent R.,Barker, David
-
supporting information
p. 5368 - 5371
(2017/11/06)
-
- Dual Palladium(II)/Tertiary Amine Catalysis for Asymmetric Regioselective Rearrangements of Allylic Carbamates
-
The streamlined catalytic access to enantiopure allylic amines as valuable precursors towards chiral β- and γ-aminoalcohols as well as α- and β-aminoacids is desirable for industrial purposes. In this article an enantioselective method is described that transforms achiral allylic alcohols and N-tosylisocyanate in a single step into highly enantioenriched N-tosyl protected allylic amines via an allylic carbamate intermediate. The latter is likely to undergo a cyclisation-induced [3,3]-rearrangement catalysed by a planar chiral pentaphenylferrocene palladacycle in cooperation with a tertiary amine base. The otherwise often indispensable activation of palladacycle catalysts by a silver salt is not required in the present case and there is also no need for an inert gas atmosphere. To further improve the synthetic value, the rearrangement was used to form dimethylaminosulfonyl-protected allylic amines, which can be deprotected under non-reductive conditions.
- Bauer, Johannes Moritz,Frey, Wolfgang,Peters, René
-
supporting information
p. 5767 - 5777
(2016/04/20)
-
- Chemo-, regio-, and stereo-selective perfluoroalkylations by a Grignard complex with zirconocene
-
The synthesis of highly reactive perfluoroalkyl Grignard reagents with early transition metal zirconocene complexes and their new types of highly chemo-, regio-, and stereo-selective perfluoroalkylation reactions are reported with epoxides in particular. The zirconocene complex is advantageous in activating the perfluoroalkyl Grignard species. The zirconocene·Grignard complexes were clarified by DOSY. Both 1H and 19F DOSY analyses show that the addition of MAO and dioxane to the mixture of RFMgCl and Cp2ZrCl2 connects Cp2Zr and RFMg to generate the zirconocene/perfluoroalkyl-Grignard/dioxane complex.
- Fujiu, Motohiro,Negishi, Kazuyuki,Guang, Jie,Williard, Paul G.,Kuroki, Shigeki,Mikami, Koichi
-
supporting information
p. 19464 - 19468
(2015/11/27)
-
- Highly Stereoselective Intermolecular Haloetherification and Haloesterification of Allyl Amides
-
An organocatalytic and highly regio-, diastereo-, and enantioselective intermolecular haloetherification and haloesterification reaction of allyl amides is reported. A variety of alkene substituents and substitution patterns are compatible with this chemistry. Notably, electronically unbiased alkene substrates exhibit exquisite regio- and diastereoselectivity for the title transformation. We also demonstrate that the same catalytic system can be used in both chlorination and bromination reactions of allyl amides with a variety of nucleophiles with little or no modification. A highly regioselective intermolecular haloetherification that proceeds with excellent enantioselectivity, catalyzed by cinchona alkaloid dimers, is reported. The regioselectivity is preserved for unbiased alkyl substituted allyl amides with either E or Z geometry. (DHQD)2PHAL=hydroquinidine 1,4-phthalazinediyl diether.
- Soltanzadeh, Bardia,Jaganathan, Arvind,Staples, Richard J.,Borhan, Babak
-
supporting information
p. 9517 - 9522
(2015/08/11)
-
- Synthesis of Novel C-Pivot Lariat 18-Crown-6 Ethers and Their Efficient Purification
-
The syntheses of various lariat ethers including several not previously reported and their efficient purification are presented. The synthesis route brings together reactions from a variety of previous works leading to a robust and generalized approach to these C-pivot lariats. The main steps are condensation of functionalized diols with pentaethylene glycol ditosylate in the presence of potassium as a templating cation. Purification of the final products was achieved without chromatography by extracting from an aqueous potassium hydroxide solution.
- Jana, Susovan,Suresh, Vallabh,Lepore, Salvatore D.
-
p. 1977 - 1980
(2015/09/01)
-
- Highly efficient preparation of selectively isotope cluster-labeled long chain fatty acids via two consecutive Csp3-Csp3 cross-coupling reactions
-
An efficient synthesis involving two copper-catalyzed alkyl-alkyl coupling reactions has been designed to easily access doubly isotope-labeled fatty acids. Such NMR- and IR-active compounds were obtained in excellent overall yields and will be further used for determining the conformation of an alkyl chain of lipidic biomolecules upon interaction with proteins.
- Lethu, Sebastien,Matsuoka, Shigeru,Murata, Michio
-
supporting information
p. 844 - 847
(2014/03/21)
-
- Asymmetric cascade reaction to allylic sulfonamides from allylic alcohols by palladium(II)/base-catalyzed rearrangement of allylic carbamates
-
A regio- and enantioselective tandem reaction is reported capable of directly transforming readily accessible achiral allylic alcohols into chiral sulfonyl-protected allylic amines. The reaction is catalyzed by the cooperative action of a chiral ferrocene palladacycle and a tertiary amine base and combines high step-economy with operational simplicity (e.g. no need for inert-gas atmosphere or catalyst activation). Mechanistic studies support a Pd II-catalyzed [3,3] rearrangement of allylic carbamates - generated in situ from the allylic alcohol and an isocyanate - as the key step, which is followed by a decarboxylation.
- Bauer, Johannes Moritz,Frey, Wolfgang,Peters, Rene
-
supporting information
p. 7634 - 7638
(2014/08/05)
-
- Total synthesis of isoquinocyclinone
-
The total synthesis of the heptacyclic natural product isoquinocyclinone has been achieved. A Hauser annulation was used to assemble the anthraquinone core structure. The unique 2,4,5,6-tetrahydropyrrolo[2,3-b]pyrrole substructure was prepared by alkyne addition to a lactone intermediate and subsequent Ni 0-mediated cyanide addition, the conversion of an O,O- into an N,O-acetal, and final intramolecular N-alkylation. Hauser annulation: An efficient total synthesis of isoquinocyclinone was achieved using a pentacyclic lactone as the key intermediate (see scheme). The pyrrolo-pyrrole substructure was elaborated by acetylide acylation, conversion of an O,O-acetal into an N,O-acetal, and intramolecular amidine alkylation.
- Dischmann, Mike,Frassetto, Timo,Breuning, M. André,Koert, Ulrich
-
supporting information
p. 11300 - 11302
(2014/10/15)
-
- Synthesis of unnatural phosphonosugar analogues
-
The first synthesis of new cyclic phosphonates (phostones), analogues of pentafuranoses containing a phosphorus atom in place of the anomeric carbon in the deoxyribose and deoxyxylose series, is described. Two methods, of respectively six and seven steps, were developed in parallel, and each gave the racemic phosphonosugars in good yields. Compounds analogous to the alpha and beta anomers were isolated and fully characterized by NMR spectroscopy. The first synthesis of unnatural phosphono-analogues of 2-deoxy ribose and the 2-deoxyxylose is reported. Two methods, of respectively six and seven steps, were developed in parallel, and each gave the racemic phosphonosugars in good yields. Compounds analogous to the α and β anomers were isolated and fully characterized by NMR spectroscopy. Copyright
- Dayde, Benedicte,Pierra, Claire,Gosselin, Gilles,Surleraux, Dominique,Ilagouma, Amadou Tidjani,Laborde, Coralie,Volle, Jean-Noel,Virieux, David,Pirat, Jean-Luc
-
p. 1333 - 1337
(2014/03/21)
-
- Synthesis of Unnatural Phosphonosugar Analogues
-
The first synthesis of new cyclic phosphonates (phostones), analogues of pentafuranoses containing a phosphorus atom in place of the anomeric carbon in the deoxyribose and deoxyxylose series, is described. Two methods, of respectively six and seven steps, were developed in parallel, and each gave the racemic phosphonosugars in good yields. Compounds analogous to the alpha and beta anomers were isolated and fully characterized by NMR spectroscopy.
- Dayde, Bndicte,Pierra, Claire,Gosselin, Gilles,Surleraux, Dominique,Ilagouma, Amadou Tidjani,Laborde, Coralie,Volle, Jean-Noel,Virieux, David,Pirat, Jean-Luc
-
p. 1333 - 1337
(2015/10/05)
-
- Catalytic asymmetric claisen rearrangement of gosteli-type allyl vinyl ethers: Total synthesis of (-)-9,10-dihydroecklonialactone B
-
The enantioselective synthesis of (-)-9,10-dihydroecklonialactone B is described. The catalytic asymmetric Claisen rearrangement of a Gosteli-type allyl vinyl ether was utilized to afford an acyclic α-keto ester building block endowed with functionality a
- Becker, Julia,Butt, Lena,Von Kiedrowski, Valeska,Mischler, Elisabeth,Quentin, Florian,Hiersemann, Martin
-
supporting information
p. 3040 - 3051
(2014/05/06)
-
- Stereoselective total synthesis of oplopandiol, oploxyne A, and oploxyne B
-
A stereoselective total synthesis of oplopandiol, oploxyne A, and (-)-oploxyne B is described. The key reactions include Sharpless asymmetric epoxidation, d-proline catalyzed aminoxylation, Cadiot-Chodkiewicz cross-coupling reaction, m-CPBA induced substrate-controlled stereoselective epoxidation, and Lewis acid catalyzed stereo- and regioselective ring-opening of epoxide.
- Reddy, B.V. Subba,Nageshwar Rao,Kumaraswamy,Yadav
-
p. 4590 - 4592
(2014/12/10)
-
- The stereochemical course and mechanism of the IspH reaction
-
On the right path: The stereochemcial course of the IspH reaction, the last reaction in the deoxyxylulose phosphate pathway to terpenes, was investigated in feeding experiments with deuterated isotopologues of 1-deoxy-D-xylulose. The results support an enzyme mechanism for IspH that involves a previously suggested metallacyclopropane intermediate. Copyright
- Citron, Christian A.,Brock, Nelson L.,Rabe, Patrick,Dickschat, Jeroen S.
-
supporting information; experimental part
p. 4053 - 4057
(2012/06/01)
-
- Silver(I)-Catalyzed deprotection of p -methoxybenzyl ethers: A mild and chemoselective method
-
The p-methoxybenzyl protecting group (PMB) on various alcohols and an acid was efficiently and selectively cleaved by the action of a catalytic amount of silver(I) hexafluoroantimonate combined with 0.5 equiv of 1,3,5- trimethoxybenzene in dichloromethane at 40 °C.
- Kern, Nicolas,Dombray, Thomas,Blanc, Aurelien,Weibel, Jean-Marc,Pale, Patrick
-
p. 9227 - 9235,9
(2012/12/12)
-
- COMPOUNDS
-
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.
- -
-
Page/Page column 60
(2012/06/01)
-
- One-pot oxidation/isomerization of Z-allylic alcohols with oxygen as stoichiometric oxidant
-
A method for generating (E)-α,β-unsaturated aldehydes from Z-allylic alcohols or E/Z-mixtures is described. The one-pot procedure involves a Cu-catalyzed oxidation followed by an organocatalytic Z/E-isomerization with N,N-dimethylaminopyridine (DMAP).
- Koenning, Daniel,Hiller, Wolf,Christmann, Mathias
-
supporting information
p. 5258 - 5261
(2013/01/15)
-
- Palladium(II)-catalyzed cycloisomerization of functionalized 1,5-hexadienes
-
Scope and limitations of the Pd(II)-catalyzed cycloisomerization of functionalized 1,5-hexadienes have been studied. In situ NMR experiments indicate a challenging competition between various reaction pathways. A careful balance between substrate structur
- Nelson, Bjoern,Hiller, Wolf,Pollex, Annett,Hiersemann, Martin
-
supporting information; experimental part
p. 4438 - 4441
(2011/10/08)
-
- Gold-catalysed activation of epoxides: Application in the synthesis of bicyclic ketals
-
Gold-catalysed generation of diol equivalents from epoxides and their intramolecular reaction with Ca≡C bonds to generate bicyclic ketals is presented. This reaction essentially involves the formation of an acetonide, which subsequently cyclises on the alkyne intramolecularly under gold catalysis conditions. This method could be extended to make optically pure bicyclic ketals. Deuterium incorporation experiments were carried out to ascertain the mechanism of the reaction. Sequential activation of epoxide and alkyne moieties by a gold catalyst in acetone as solvent has been achieved. This strategyhas been employed to synthesise bicyclic ketals from epoxy alkynes. Copyright
- Balamurugan, Rengarajan,Kothapalli, Raveendra Babu,Thota, Ganesh Kumar
-
supporting information; scheme or table
p. 1557 - 1569
(2011/04/25)
-
- Selectivity in the addition reactions of organometallic reagents to aziridine-2-carboxaldehydes: The effects of protecting groups and substitution patterns
-
Good to excellent stereoselectivity has been found in the addition reactions of Grignard and organozinc reagents to N-protected aziridine-2-carboxaldehydes. Specifically, high syn selectivity was obtained with benzyl-protected cis, tert-butyloxycarbonyl-protected trans, and tosyl-protected 2,3-disubstituted aziridine-2-carboxaldehydes. Furthermore, rate and selectivity effects of ring substituents, temperature, solvent, and Lewis acid and base modifiers were studied. The diastereomeric preference of addition is dominated by the substrate aziridines' substitution pattern and especially the electronic character and conformational preferences of the nitrogen protecting groups. To help rationalize the observed stereochemical outcomes, conformational and electronic structural analyses of a series of model systems representing the various substitution patterns have been explored by density functional calculations at the B3LYP/6-31G* level of theory with the SM8 solvation model to account for solvent effects. Grignard and bear it: Good to excellent stereoselectivity is reported for the addition reactions of Grignard and organozinc reagents to N-protected aziridine-2-carboxaldehydes (see scheme). High syn selectivity was obtained with benzyl-protected cis, tert-butyloxycarbonyl-protected trans, and tosyl-protected 2,3-disubstituted aziridine-2-carboxaldehydes. Copyright
- Kulshrestha, Aman,Schomaker, Jennifer M.,Holmes, Daniel,Staples, Richard J.,Jackson, James E.,Borhan, Babak
-
supporting information; experimental part
p. 12326 - 12339
(2011/12/15)
-
- Synthesis of 3, 5-diazabicyclo [5.1.0] octenes. A new platform to mimic glycosidase transition states
-
All-cis 1-hydroxymethyl 2, 3 bis-aminomethyl cyclopropane was used to construct the first 3, 5- diazabicyclo [5.1.0]-3-octenes. This system has the interesting ability to exist in a conformation that resembles a snapshot of a glycoside hydrolysis reaction
- Leonik, Fedra M.,Ghiviriga, Ion,Horenstein, Nicole A.
-
experimental part
p. 5566 - 5572
(2010/11/18)
-
- Application of a chiral scaffolding ligand in catalytic enantioselective hydroformylation
-
The synthesis of β-amino-aldehydes has been achieved through enantioselective hydroformylation of PMP-protected allylic amines. The reaction is accomplished by using a scalemic scaffolding ligand that covalently and reversibly binds to the substrate. These ligands behave like chiral auxiliaries because they are covalently attached to the substrate during hydroformylation; however, similar to traditional asymmetric ligands, they can be used in catalytic quantities. The directed hydroformylation of disubstituted olefins occurs under mild conditions (35 °C and 50 psi CO/H2), and Z-olefins afford excellent enantioselectivities (up to 93% ee).
- Worthy, Amanda D.,Joe, Candice L.,Lightburn, Thomas E.,Tan, Kian L.
-
supporting information; experimental part
p. 14757 - 14759
(2010/12/19)
-
- Stereoselective formal total synthesis of novel antibiotic (-)-centrolobine
-
A concise and stereoselective formal total synthesis of (-)-centrolobine is achieved utilizing Mioskowski's Lewis acid mediated epoxide opening followed by ring-closing metathesis as the key reaction.
- Mohapatra, Debendra K.,Pal, Rita,Rahaman, Hasibur,Gurjar, Mukund K.
-
body text
p. 219 - 227
(2010/05/03)
-
- Stereoselective total synthesis of (+)-anamarine via cross-metathesis protocol
-
A convergent stereoselective total synthesis of (+)-anamarine via cross-metathesis (CM) protocol starting from 2-butyn-1,4-diol and vinyl lactone is reported. Other key features of the strategy include the use of Sharpless asymmetric epoxidation, Sharples
- Sabitha, Gowravaram,Reddy, C. Nagendra,Gopal, Peddabuddi,Yadav
-
scheme or table
p. 5736 - 5739
(2010/11/16)
-
- Iridium-catalyzed regio- and enantioselective N-allylation of indoles
-
Iridium is blind to C: Highly regio- and enantioselective, iridium-catalyzed N-allylations of indoles, which complement the more common reactivity of indoles as carbon nucleophiles, have been developed (see scheme). These reactions form highly enantioenri
- Stanley, Levi M.,Hartwig, John F.
-
supporting information; body text
p. 7841 - 7844
(2010/04/02)
-
- Allylic fluorination via an unusual alkene Z/E isomerisation
-
The isomerisation of readily available (Z)-4-(para-methoxybenzyloxy)-1-chloro-2-butene was achieved under mild conditions to afford the much less accessible E-diastereoisomer. This was an effective substrate in Sharpless asymmetric dihydroxylation (AD) re
- Laurenson, James A.B.,Meiries, Sebastien,Percy, Jonathan M.,Roig, Ricard
-
scheme or table
p. 3571 - 3573
(2009/12/01)
-
- The P1 N-isopropyl motif bearing hydroxyethylene dipeptide isostere analogues of aliskiren are in vitro potent inhibitors of the human aspartyl protease renin
-
Novel nonpeptide small molecule renin inhibitors bearing an N-isopropyl P1 motif were designed based on initial lead structures 1 and aliskiren (2). (P3-P1)-Benzamide derivatives such as 9a and 34, as well as the corresponding P1 basic tertiary amine derivatives 10 and 35 were found to display low nanomolar inhibition against human renin in vitro.
- Yamaguchi, Yasuchika,Menear, Keith,Cohen, Nissim-Claude,Mah, Robert,Cumin, Frédéric,Schnell, Christian,Wood, Jeanette M.,Maibaum, Jürgen
-
scheme or table
p. 4863 - 4867
(2010/05/18)
-
- N-heterocyclic carbene-catalyzed hydroacylation of unactivated double bonds
-
(Chemical Equation Presented) An intramolecular N-heterocyclic carbene (NHC)-catalyzed hydroacylation of unactivated double bonds is reported. Systematic variation of the catalyst structure revealed an N- mesitylthiazolylidene annulated with a seven-membered ring to be especially reactive. This NHC enables a unique C-C bond-forming reaction to afford substituted chroman-4-ones in moderate to excellent yields, even ones containing all-carbon quaternary centers.
- Hirano, Keiichi,Biju, Akkattu T.,Piel, Isabel,Glorius, Frank
-
supporting information; experimental part
p. 14190 - 14191
(2010/02/15)
-
- An asymmetric total synthesis of brevisamide
-
An enantioselective synthesis of marine alkaloid brevisamide was accomplished in a convergent manner. The synthesis utilized an enantioselective hetero-Diels - Alder reaction which sets three chiral centers in compound 11. The synthesis also features a modified Wolff-Kishner reduction, Rubottom oxidation, and Suzuki - Miyaura coupling to furnish brevisamide.
- Ghosh, Arun K.,Li, Jianfeng
-
supporting information; experimental part
p. 4164 - 4167
(2009/12/31)
-
- Synthesis of N-heterocycles, beta-amino acids, and allyl amines via aza-payne mediated reaction of ylides and hydroxy aziridines
-
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under the basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring closure yields the desired pyrrolidine, thus completing the relay of the 3-membered the 5-membered nitrogen containing ring system. This process takes place with complete transfer of stereochemical fidelity, and can be applied to sterically hindered aziridinols.
- -
-
Page/Page column 17
(2009/01/23)
-
- Enantiocontrolled synthesis of polychlorinated hydrocarbon motifs: A nucleophilic multiple chlorination process revisited
-
Polychlorinated hydrocarbon motifs have been synthesized in enantiomerically pure forms by means of nucleophilic multiple chlorinations of chiral epoxides, which stereospecifically incorporate halogen atoms into oxygenated molecular scaffolds. The present
- Yoshimitsu, Takehiko,Fukumoto, Naoya,Tanaka, Tetsuaki
-
supporting information; experimental part
p. 696 - 702
(2009/06/28)
-
- Catalytic enantioselective allylation of dienals through the intermediacy of unsaturated π-allyl complexes
-
(Chemical Equation Presented) The nickel-catalyzed enantioselective addition of allylboronic acid pinacol ester [allylB(pin)] to >,β,γ,δ-unsaturated aldehydes is described. This reaction results in a remarkable inversion of substrate olefin geometry, providing the Z,E-configured reaction product in good enantioselectivity and olefin stereoselectivity. The reaction appears to proceed by conversion of the dienal to an unsaturated B-allyl complex followed by reductive elimination via transition state II. Enantioselectivities range from 73-94% ee for a range of δ-substituted dienals when chiral ligand L3 is employed.
- Zhang, Ping,Morken, James P.
-
supporting information; scheme or table
p. 12550 - 12551
(2010/01/30)
-
- Solvent-dependent reactivity in porcine pancreatic lipase (PPL)-catalyzed hydrolysis
-
The solvent-dependent enzyme reactivity of porcine pancreatic lipase (PPL)-catalyzed hydrolysis was investigated using trans-3 and cis-(3-(benzyloxymethyl)oxiran-2-yl)methyl acetate 4 as substrates. The conversion efficiency and enantioselectivity of the
- Shen, Liu-Lan,Wang, Fang,Mun, Han-Seo,Suh, Myungkoo,Jeong, Jin-Hyun
-
p. 1647 - 1653
(2008/12/21)
-
- Allyl sulfides are privileged substrates in aqueous cross-metathesis: Application to site-selective protein modification
-
Allyl sulfides undergo efficient cross-metathesis in aqueous media with Hoveyda-Grubbs second generation catalyst 1. The high reactivity of allyl sulfides in cross-metathesis was exploited in the first examples of cross-metathesis on a protein surface. S-Allylcysteine was incorporated chemically into the protein, providing the requisite allyl sulfide handle. Preliminary efforts to genetically incorporate S-allylcysteine into proteins are also reported. Copyright
- Lin, Yuya A.,Chalker, Justin M.,Floyd, Nicola,Bernardes, Goncalo J. L.,Davis, Benjamin G.
-
supporting information; experimental part
p. 9642 - 9643
(2009/02/04)
-
- Diastereomerically and enantiomerically pure 2,3-disubstituted pyrrolidines from 2,3-aziridin-1-ols using a sulfoxonium ylide: A one-carbon homologative relay ring expansion
-
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine, thus completing the relay of the three-membered to the five-membered nitrogen-containing ring system. This process takes place with complete transfer of stereochemical fidelity and can be applied to sterically hindered aziridinols.
- Schomaker, Jennifer M.,Bhattacharjee, Somnath,Yan, Jun,Borhan, Babak
-
p. 1996 - 2003
(2007/10/03)
-
- Tetrasubstituted pyrrolidines via a tandem aza-Payne/hydroamination reaction
-
A facile tandem aza-Payne/hydroamination reaction of aziridinol is reported, which yields highly functionalized pyrrolidines. Addition of alkynyl Grignards to 2,3-aziridinals yields, in most cases, high syn to anti ratios of the aziridinol. Treatment of the syn-aziridinol with base leads initially to an aza-Payne rearrangement, which juxtaposes the amine and the alkyne in favorable orientation to complete the hydroamination. The anti-aziridinol undergoes the aza-Payne rearrangement, but cannot proceed further with the hydroamination. Copyright
- Schomaker, Jennifer M.,Geiser, Andrea R.,Huang, Rui,Borhan, Babak
-
p. 3794 - 3795
(2008/02/01)
-
- Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue
-
The preparation of the versatile aldehyde 15 via a concise route based on a formal anti-asymmetric aminohydroxylation and its use in a 5-step synthesis of a cytotoxic C12 analogue of the natural anhydrophytosphingosine jaspine B is presented.
- Genisson, Yves,Lamande, Lydia,Salma, Yahya,Andrieu-Abadie, Nathalie,Andre, Chantal,Baltas, Michel
-
p. 857 - 864
(2008/02/09)
-
- An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol
-
An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol has been devised. This new route increases the throughput and yield of the diene product by circumventing a low yielding preparation of boronic acid intermediate as well as removing the need to use multi-gram quantities of highly toxic thallium salts. In the process of developing this new route, a higher yielding preparation of (E)-3-hydroxyprop-1-enylboronic acid was also achieved.
- Clarke, Paul A.,Rolla, Gabriele A.,Cridland, Andrew P.,Gill, Andrew A.
-
p. 9124 - 9128
(2008/02/10)
-
- Enantioselective synthesis of the C8-C20 segment of curvicollide C
-
The enantioselective synthesis of the C8-C20 fragment of curvicollide C has been accomplished. A catalytic asymmetric Claisen rearrangement (CAC), a diastereoselective methyl cupration of an alkynoate, and a Julia-Kocienski olefination served as key C/C-connecting transformations.
- Koerner, Marleen,Hiersemann, Martin
-
p. 4979 - 4982
(2008/03/28)
-
- Mild and chemoselective deacetylation method using a catalytic amount of acetyl chloride in methanol
-
Efficient deacetylation of alcohol acetates under mild acidic conditions was accomplished with a catalytic amount of acetyl chloride in methanol. Acetates of various primary, secondary, aromatic and sugar alcohols were successfully deprotected. Highly chemoselective removal of acetyl groups in presence of other commonly employed esters was also achieved in excellent yields. The reactivity of this transesterification-mediated deacetylation was found to be directly dependent upon the electronic and steric nature of the acetates. Georg Thieme Verlag Stuttgart.
- Yeom, Chang-Eun,Lee, So Young,Kim, Young Jong,Kim, B. Moon
-
p. 1527 - 1530
(2007/10/03)
-
- Ester dienolate [2,3]-Wittig rearrangement in natural product synthesis: Diastereoselective total synthesis of the triester of viridiofungin A, A 2, and A4
-
An ester dienolate [2,3]-Wittig rearrangement was utilized to access the alkylated citric acid skeleton 6 that is characteristic for the viridiofungins and other members of the alkyl citrate family of secondary natural products. The [2,3]-sigmatropic rearrangement of (Z,Z)-15 provided the rearrangement product (±)-syn-16 in moderate yield and with very good diastereoselectivity. A Julia-Kocienski olefination efficiently served to connect the polar head (±)-syn-26 with the lipophilic tail (32a-c) of the viridiofungins. Amide formation between the racemic viridiofungin precursors 35a-c and the enantiomerically pure amino acid L-tyrosine methyl ester followed by preparative reversed-phase HPLC provided the isopropyl dimethyl ester of viridiofungin A ((+)-39a), A2 ((+)-39b), and A4 ((+)-39c) as well as the nonnatural diastereomers (-)-38a-c.
- Pollex, Annett,Millet, Agnes,Mueller, Jana,Hiersemann, Martin,Abraham, Lars
-
p. 5579 - 5591
(2007/10/03)
-
- Thioureas as ligands in the Pd-catalyzed intramolecular Pauson-Khand reaction
-
(Chemical Equation Presented) The thiourea-Pd complex was established as a novel type of catalyst in the PKR of allylpropargylamine, and the demonstrated chemistry may prove to be valuable for developing thiuorea as a ligand for the Pd-catalyzed Pauson-Kh
- Tang, Yefeng,Deng, Lujiang,Zhang, Yangdong,Dong, Guangbin,Chen, Jiahua,Yang, Zhen
-
p. 1657 - 1659
(2007/10/03)
-
- Efficient chemoselective deprotection of silyl ethers using catalytic 1-chloroethyl chloroformate in methanol
-
Fast and chemoselective desilylation of silyl-protected alcohols was achieved using a catalytic amount of 1-chloroethyl chloroformate in methanol. With a minimal amount of 1-chloroethyl chloroformate as the source for anhydrous HCl, extremely efficient cleavage of silyl ethers of primary and secondary alcohols was accomplished, and chemoselective deprotection of one silyl ether in the presence of another silyl or other acid-labile group was possible through controlling the amount of the chloroformate and reaction time.
- Yeom, Chang-Eun,Kim, Young Jong,Lee, So Young,Shin, Yong Je,Kim, B. Moon
-
p. 12227 - 12237
(2007/10/03)
-
- Furanose Synthesis via Regioselective Dihydroxylation of 1-Silyloxy-1,3-dienes: Application to the Furanose Unit of 4-epi-Hygromycin A
-
Asymmetric dihydroxylation of a 1-silyloxy-1,3-diene is shown to occur regioselectively on the non-oxygenated alkene. Second dihydroxylation is complicated by over-oxidation to the dione and epimerisation of reaction products. However, subsequent manipula
- Armstrong, Alan,Gethin, David M.,Wheelhouse, Christopher J.
-
p. 350 - 352
(2007/10/03)
-