- A Diels-Alder macrocyclization enables an efficient asymmetric synthesis of the antibacterial natural product abyssomicin C
-
An efficient and highly diastereoselective intramolecular Diels-Alder reaction is the basis of a concise asymmetric synthesis of the potent antibacterial natural product abyssomicin C (see formula). The complexity of the target structure was reduced to three fragments and required two carbonyl addition reactions to achieve key bond formations. (Figure Presented).
- Zapf, Christoph W.,Harrison, Bryce A.,Drahl, Carmen,Sorensen, Erik J.
-
-
Read Online
- Palladium-Catalyzed Three Carbon Chain Extension Reactions with Acrolein Acetals. A Convenient Synthesis of Conjugated Dienals
-
A variety of vinylic halides has been found to react with acrolein or methacrolein acetals and amines with palladium catalysts to form 5-amino 3-enal acetals and/or dienal acetals.The reaction products yield 2,4-dienals on treatment with aqueous acids, in moderate to good yields.Crotonaldehyde dimethyl acetal also undergoes the reaction, but only in low yields. 3-Buten-2-one ethylene ketal reacted well under the same conditions, however, and Hofmann elimination and hydrolysis of the product amine gave (E,E)-3,5-heptadien-2-one in 90percent yield.
- Patel, Babu A.,Kim, Jin-Il I.,Bender, Diana D.,Kao, Lien-Chung,Heck, Richard F.
-
-
Read Online
- Cu(II)-catalyzed selective aerobic oxidation of alcohols under mild conditions
-
Aerobic Alcohol Oxidation. An efficient four-component system consisting of acetamido-TEMPO/Cu(ClO4)2/TMDP/DABCO in DMSO has been developed for room-temperature aerobic alcohol oxidation. Under the optimal conditions, various alcohols could be converted into their corresponding aldehydes or ketones in good to excellent yields. The newly developed catalytic system could also be recycled and reused for three runs without any significant loss of catalytic activity.
- Jiang, Nan,Ragauskas, Arthur J.
-
-
Read Online
- Ambruticins: tetrahydropyran ring formation and total synthesis
-
The ambruticins are a family of polyketide natural products which exhibit potent antifungal activity. Gene knockout experiments are in accord with the proposal that the tetrahydropyran ring of the ambruticins is formedviathe AmbJ catalysed epoxidation of the unsaturated 3,5-dihydroxy acid, ambruticin J, followed by regioselective cyclisation to ambruticin F. Herein, a convergent approach to the total synthesis of ambruticin J is described as well as model studies involving epoxidation and cyclisations of unsaturated hydroxy esters to give tetrahydropyrans and tetrahydrofurans. The total synthesis involves preparation of three key fragments which were unitedviaa Suzuki-Miyaura cross-coupling and Julia-Kocienski olefination to generate the required carbon framework. Global deprotection to a triol and selective oxidation of the primary alcohol gave, after hydrolysis of the lactone, ambruticin J.
- Bowen, James I.,Crump, Matthew P.,Wang, Luoyi,Willis, Christine L.
-
supporting information
p. 6210 - 6215
(2021/07/28)
-
- Step-Economic Synthesis of Biomimetic β-Ketopolyene Thioesters and Demonstration of Their Usefulness in Enzymatic Biosynthesis Studies
-
Studies on the biosynthetic processing of polyene thioester intermediates are complicated by limited access to appropriate substrate surrogates. We present a step-economic synthetic access to biomimetic β-ketopolyene thioesters that is based on an Ir-catalyzed reductive Horner-Wadsworth-Emmons olefination. New β-ketotriene and pentaenethioates of pantetheine and N-acetylcysteamine were exemplarily synthesized via short and concise routes. The usefulness of these compounds was demonstrated in an in vitro assay with the ketoreductase domain MycKRB from mycolactone biosynthesis.
- Hahn, Frank,Ro?, Theresa,Schr?der, Marius,Wunderlich, Johannes
-
-
- Length-Selective Synthesis of Acylglycerol-Phosphates through Energy-Dissipative Cycling
-
The main aim of origins of life research is to find a plausible sequence of transitions from prebiotic chemistry to nascent biology. In this context, understanding how and when phospholipid membranes appeared on early Earth is critical to elucidating the prebiotic pathways that led to the emergence of primitive cells. Here we show that exposing glycerol-2-phosphate to acylating agents leads to the formation of a library of acylglycerol-phosphates. Medium-chain acylglycerol-phosphates were found to self-assemble into vesicles stable across a wide range of conditions and capable of retaining mono- and oligonucleotides. Starting with a mixture of activated carboxylic acids of different lengths, iterative cycling of acylation and hydrolysis steps allowed for the selection of longer-chain acylglycerol-phosphates. Our results suggest that a selection pathway based on energy-dissipative cycling could have driven the selective synthesis of phospholipids on early Earth.
- Bonfio, Claudia,Caumes, Cécile,Duffy, Colm D.,Patel, Bhavesh H.,Percivalle, Claudia,Tsanakopoulou, Maria,Sutherland, John D.
-
supporting information
p. 3934 - 3939
(2019/03/08)
-
- Synthesis of Tetradecapentaenoic Acid Derivatives
-
A 12-stage method for the stereoselective synthesis of tetradecapentaenoic acid derivatives using phosphoric reagents was developed. The key step in the synthesis is the Z-selective Wittig reaction between sorbaldehyde and triphenylphosphonium (6-methoxycarbonyl)hexanilide, as well as the Ramirez-Corey-Fuchs reaction and the Trost-Kazmaier rearrangement. The synthesized (2E,4E,8Z,10E,12E)-N-isobutyltetradeca-2,4,8,10,12-pentaenamide corresponds to a natural compound called γ-Sansho?l.
- Kolodyazhnaya,Kolodyazhny
-
p. 1998 - 2004
(2019/11/29)
-
- METHOD FOR PRODUCING 2,4-DIENAL ACETAL COMPOUND AND 2,4-DIENAL COMPOUND
-
Methods of producing a 2,4-dienal acetal compound and a 2,4-dienal compound useful as synthesis intermediates of a sex pheromone compound having a conjugated diene structure or a conjugated triene structure. More specifically, a method produces a 2,4-dienal acetal compound of Formula (2): R1CH═CH—CH═CH—CH(OR2)(OR3), including a step of subjecting a 2-enal acetal compound having a leaving group X at position C5 and being expressed by Formula (1): R1CHX—CH2—CH═CH—CH(OR2)(OR3) to an elimination reaction in the presence of a base to obtain the 2,4-dienal acetal compound (2); and a method for producing a 2,4-dienal compound of Formula (3): R1CH═CH—CH═CH—CHO, further including a step of deprotecting the 2,4-dienal acetal compound (2) to obtain the 2,4-dienal compound (3).
- -
-
Paragraph 0128-0132
(2018/11/21)
-
- CONVERSION OF ALCOHOLS TO LINEAR AND BRANCHED FUNCTIONALIZED ALKANES
-
Embodiments herein concerns the eco-friendly conversion of simple alcohols to linear or branched functionalized alkanes, by integrated catalysis. The alcohols are firstlyoxidized either chemically or enzymatically to the corresponding aldehydes or ketones, followed by aldol condensations using a catalyst to give the corresponding enals or enones. The enals or enones are subsequently and selectively hydrogenated using a recyclable heterogeneous metal catalyst, organocatalyst or an enzyme to provide linear or branched functionalized alkanes with an aldehyde, keto- or alcohol functionality. The process is also iterative and can be further extended by repeating the above integrated catalysis for producing long-chain functionalized alkanes from simple alcohols.
- -
-
Page/Page column 9
(2018/03/09)
-
- Synthesis of trans-Configured Enol Ethers by a Sequence of syn-Selective Glycolate Aldol Addition, Hydrolysis, and Grob Fragmentation
-
A trans-selective access to enol ethers with a disubstituted C=C bond was developed. It consists of a diastereoselective glycolate aldol addition, a hydrolysis, and a Grob fragmentation. Aldol additions of N-[(benzyloxy)acetyl]oxazolidinones furnished syn-aldols selectively. Hydrolytic removal of the auxiliaries gave α-benzyloxy-β-hydroxycarboxylic acids. Exposure to DMF dineopentylacetal induced Grob fragmentations, which delivered trans-configured enol ethers. Applying our 3-step sequence in a bidirectional synthesis led to bis(enol ethers) trans,trans-selectively, i.e., to a motif rarely encountered in the literature. A modified precursor synthesis allowed for the first time to access both the E- and the Z-isomer of an enol ether with a trisubstituted C=C bond stereoselectively using a Grob fragmentation route. The Ar–Br and C≡C–SiMe2tBu motifs of appropriate enol ethers engaged in follow-up reactions via organometallics. These provided more elaborated enol ethers.
- Engesser, Tobias,Brückner, Reinhard
-
supporting information
p. 5789 - 5794
(2017/10/23)
-
- Oxo-rhenium catalyzed reductive coupling and deoxygenation of alcohols
-
Representative benzylic, allylic and α-keto alcohols are deoxygenated to alkanes and/or reductively coupled to alkane dimers by reaction with PPh3 catalyzed by (PPh3)2ReIO2 (1). The newly discovered catalytic reductive coupling reaction is a rare C-C bond-forming transformation of alcohols.
- Kasner, Gabrielle R.,Boucher-Jacobs, Camille,Michael McClain,Nicholas, Kenneth M.
-
supporting information
p. 7257 - 7260
(2016/06/09)
-
- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
-
The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
- -
-
-
- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
-
The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
- -
-
-
- Selective Oxidation of Benzylic and Allylic Alcohols Using Mn(OAc) 3/Catalytic 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
-
A practical, chemoselective oxidation of alcohols employing catalytic quantities of DDQ as the oxidant and Mn(OAc)3 as the co-oxidant is described. Electron-rich benzylic alcohols are oxidized efficiently to their corresponding carbonyls, but less electron-rich benzylic alcohols remain unchanged. Allylic alcohols are rapidly oxidized to their corresponding aldehyde or ketone counterparts in high yields. This protocol is operationally simple, employs an inexpensive source of Mn(OAc)3, has short reaction times, and exhibits a significant chemoselectivity favoring allylic alcohols over benzylic alcohols. This procedure also avoids the use of very large excesses of reagents and sometimes poor reproducibility that characterize previously developed reagents such as MnO2
- Cosner, Casey C.,Cabrera, Pablo J.,Byrd, Katherine M.,Adams Thomas, Asia M.,Helquist, Paul
-
supporting information; experimental part
p. 2071 - 2073
(2011/06/19)
-
- Acidic ionic liquid-catalyzed homologation of the polyene chain in α,β-enals (polyenals)
-
An efficient green-chemistry synthesis of conjugated polyenals from α,β-enals, orthoesters, and alkyl vinyl ethers promoted by acidic ionic liquid [emim][HSO4] is described. The ionic liquid can be reused at least three times without any decrease in product yields.
- Kryshtal, Galina V.,Zhdankina, Galina M.,Ignat'Ev, Nikolai V.,Schulte, Michael,Zlotin, Sergei G.
-
experimental part
p. 173 - 178
(2011/02/27)
-
- Silica gel-mediated rearrangement of allylic acetates. Application to the synthesis of 1,3-enynes
-
Silica gel was found to efficiently promote the rearrangement of allylic acetates into their most stable regioisomers under microwave irradiation. The reaction is easy to perform and eco-friendly. This method was applied to the metal-free synthesis of 1,3-enynes.
- Serra-Muns, Anna,Guerinot, Amandine,Reymond, Sebastien,Cossy, Janine
-
supporting information; experimental part
p. 4178 - 4180
(2010/08/07)
-
- Copper(II)-catalyzed aerobic oxidation of primary alcohols to aldehydes in ionic liquid [bmpy]PF6
-
(Chemical Equation Presented) A room-temperature aerobic oxidation of primary alcohols to aldehydes catalyzed by the three-component system acetamido-TEMPO/Cu-(ClO4)2/DMAP in the ionic liquid [bmpy]PF6 has been developed, and the catalysts can be recycled and reused for five runs without any significant loss of catalytic activity.
- Jiang, Nan,Ragauskas, Arthur J.
-
p. 3689 - 3692
(2007/10/03)
-
- POLYUNSATURATED LINEAR ALDEHYDES AND THEIR DERIVATIVES WITH ANTI-RADICAL AND ANTI-TUMORAL ACTIVITY
-
The invention relates to polyunsaturated linear aldehydes and derivatives thereof which can be extracted from the feathers or tissues of parrots of prepared synthetically with antioxidant, antitumoral and anti-inflammatory activity, and which are useful in the prevention and treatment of cardiovascular, inflammatory, atherosclerotic, proliferative cell and tumour damage and the prevention of alterations caused by ageing.
- -
-
Page/Page column 4-6
(2008/06/13)
-
- Proline-catalyzed one-step asymmetric synthesis of 5-hydroxy-(2E)-hexenal from acetaldehyde
-
For the first time, the L-proline-catalyzed direct asymmetric self-aldolization of acetaldehyde is described affording (+)-(5S)-hydroxy-(2E)-hexenal 2 with ee's ranging from 57 to 90%. Further transformations of 2 into synthetically valuable building bloc
- Cordova, Armando,Notz, Wolfgang,Barbas III, Carlos F.
-
p. 301 - 303
(2007/10/03)
-
- Synthesis and hydrolysis of [alkenyl(alkoxy)carbene]manganese complexes: Evidence for a transient allylic intermediate on the way to α,β-unsaturated aldehydes
-
A variety of alkenylcarbene complexes [Cp'(CO)2Mn= C(OEt)CH=CHR] (3) (Cp' = TiS-MeCsH4) was obtained in a straightforward manner upon aldol condensation of [Cp'(CO)2Mn=C(OEt)CH3] (1) with aromatic and α,β- unsaturated aldehydes RC(H)O (2). The reaction is totally stereoselective, giving (E)- or (all-E)-alkenylcarbenes only. The protonation of 3 at low temperature followed by reaction with water affords the α,β-unsaturated aldehyde complexes [Cp'(CO)2Mn(n2-RCH=CHCHO] (5), from which the aldehydes RC(H)=C(H)C(H)O (6) were displaced by acetonitrile. The intermediate aldehyde complexes are shown to result from the hydrolysis of a transient cationic π- allyl species [Cp'(CO)2Mn(n3-RCHCHC(OEt)H]+ ([4]+) formed upon protonation of 3.
- Mongin, Carole,Ortin, Yannick,Lugan, Noel,Mathieu, Rene
-
p. 739 - 742
(2007/10/03)
-
- Highly efficient oxidation of alcohols and aromatic compounds catalysed by the Ru-Co-Al hydrotalcite in the presence of molecular oxygen
-
The ruthenium hydrotalcite having cobalt cations, Ru-Co-Al-CO3 HT, is an effective heterogeneous catalyst for the oxidation of various kinds of alcohols in the presence of molecular oxygen.
- Matsushita, Tsuyoshi,Ebitani, Kohki,Kaneda, Kiyotomi
-
p. 265 - 266
(2007/10/03)
-
- New vanadium oxazoline catalysts for epoxidation of allylic alcohols
-
The new vanadium complexes, VO(hoz)2 1 and VO(hoz)2Cl 2 (hoz=2-(2'-hydroxyphenyl)-2-oxazoline), catalyze the epoxidation of allylic alcohols with tert-butylhydroperoxide. Catalyst 2 with the oxidation state (V) exhibits superior activity in comparison to 1, producing yields from 88 to >99% under mild conditions, 60°C and non-dry solvent.
- Hwang, Jung H.,Abu-Omar, Mahdi M.
-
p. 8313 - 8316
(2007/10/03)
-
- Catalysis of giant palladium cluster complexes, highly selective oxidations of primary allylic alcohols to (α,β-unsaturated aldehydes in the presence of molecular oxygen
-
A giant Pd cluster, Pd561phen60(OAc)180 has high catalytic activity for the selective oxidations of various primary allylic alcohols to the corresponding α,β-unsaturated aldehydes in the presence of molecular oxygen under mild reaction conditions. A Pd cluster anchored on TiO2, also catalyzes the above oxidations; the heterogeneous Pd561 cluster catalyst is easily separated from the reaction mixture and is reusable.
- Kaneda, Kiyotomi,Fujie, Yoko,Ebitani, Kohki
-
p. 9023 - 9026
(2007/10/03)
-
- Two-Carbon Homologation of Aldehydes. Synthesis of trans-α,β-Unsaturated Aldehydes
-
2-tri-n-Butylstannylvinyl ethers are useful synthetic equivalents of acetaldehyde in 2-carbon homologation reactions.When reacted with aldehydes in the presence of BF3-OEt2 the corresponding trans-α,β-unsaturated aldehydes are obtained in high yield.
- Cabezas, Jorge A.,Oehischlager, Allan C.
-
p. 5127 - 5130
(2007/10/02)
-
- A Simple and Highly Stereoselective Route to E-α,β-Unsaturated Aldehydes
-
Zinc bromide mediated reaction of α,α-bis(trimethylsilyl)-tert-butylacetaldimine (3) with a wide range of aldehydes takes place under mild conditions and affords the corresponding α,β-unsaturated aldehydes in good yields and with high E stereoselectivity (>98percent).This procedure is successfully applied to the preparation of intermediates for retinoid and natural product synthesis.
- Bellassoued, Moncef,Majidi, Assieh
-
p. 2517 - 2522
(2007/10/02)
-
- Stereoselective synthesis of (3E,5E)-dien-2-ones and (2E,4E)-dienals via 2-phenylsulfonyl 1,3-dienes
-
Michael addition of nitroalkanes to 2-phenylsulfonyl 1,3 dienes proceeded smoothly in the presence of DBU to give nitrosulfones (e.g. 2) in high yield. Transformation of the nitro group of the adduct to a keto function (Nef type reaction) and subsequent elimination of benzenesulfinic acid afforded conjugated dienones and dienals with high stereoselectivity.
- Baeckvall, Jan-E.,Ericsson, Anna M.,Plobeck, Niklas A.,Juntunen, Seppo K.
-
p. 131 - 134
(2007/10/02)
-
- Conjugated dienols
-
Conjugated dienols for providing cure sites to air-drying acrylic finishes are prepared from conjugated dienoic acids by conversion to an activated ester followed by sodium borohydride reduction thereof.
- -
-
-
- Novel Synthesis of (Z)-3-Hexen-1-ol and cis-Jasmone
-
Both (Z)-3-hexen-1-ol and cis-jasmone were synthesised via 1,4-selective hydrogenation of conjugated dienes in the presence of arene Cr(CO)3 or Cr(CO)6 catalysts as the key step.
- Furuhata, Akimichi,Onishi, Ken,Fujita, Akira,Kogami, Kunio
-
p. 1757 - 1760
(2007/10/02)
-