38112-60-6Relevant articles and documents
A One-Pot Synthesis of α,β-Unsaturated Esters From Esters
Hong, Chang Whee,Lee, Yong Jin,An, Duk Keun
, p. 1121 - 1125 (2021/06/01)
A convenient method for reductive Horner–Wadsworth–Emmons (HWE) olefination is described. The E-selective HWE homologation of various esters to α,β-unsaturated esters was readily achieved and gave the desired products in good-to-moderate yields under mild conditions. The one-pot reaction proceeds through an in situ generated aldehyde, formed via the partial reduction of an ester with lithium diisobutyl-t-butoxyaluminum hydride. The formation of cyclized metal acetal and subsequent decompose to the aldehyde for the olefination was found to be a crucial step in this C2-carbon homologation protocol.
Nickel-Catalyzed Decarboxylative Alkenylation of Anhydrides with Vinyl Triflates or Halides
Chen, Hui,Sun, Shuhao,Liao, Xuebin
supporting information, p. 3625 - 3630 (2019/05/24)
Decarboxylative cross-coupling of aliphatic acid anhydrides with vinyl triflates or halides was accomplished via nickel catalysis. This methodology works well with a broad array of substrates and features abundant functional group tolerance. Notably, our approach addresses the issue of safe and environmental installation of methyl or ethyl group into molecular scaffolds. The method possesses high chemoselectivity toward alkyl groups when aliphatic/aromatic mixed anhydrides are involved. Furthermore, diverse ketones could be modified with our strategy.
Copper-Catalyzed Perfluoroalkylation of Allyl Phosphates with Stable Perfluoroalkylzinc Reagents
Liu, Lihua,Bao, Xifei,Xiao, Hua,Li, Junlan,Ye, Feifan,Wang, Chaoqin,Cai, Qinhua,Fan, Shilu
, p. 423 - 434 (2019/01/08)
A general and practical method for copper-catalyzed cross-coupling of allyl phosphates with stable perfluoroalkylzinc reagents has been developed. The reaction proceeds under mild reaction conditions with high efficiency, good functional group tolerance, and high regio- A nd stereoselectivities and provides general, straightforward, and useful access to allyl-perfluoroalkyl compounds. Preliminary mechanistic studies reveal that the allyl copper intermediate may be involved in the catalytic cycle.
Synthesis and evaluation of analogues of the glycinocin family of calcium-dependent antibiotics
Corcilius, Leo,Liu, Dennis Y.,Ochoa, Jessica L.,Linington, Roger G.,Payne, Richard J.
, p. 5310 - 5320 (2018/08/03)
The glycinocins are a class of calcium-dependent, acidic cyclolipopeptide antibiotics that are structurally related to the clinically approved antibiotic daptomycin. In this article, we describe the synthesis of a small library of glycinocin analogues that differ by variation in the exocyclic fatty acyl substituent. The glycinocin analogues were screened against a panel of Gram-positive bacteria (as well as Gram-negative P. aeruginosa). These analogues exhibited similar calcium-dependent activity to the parent natural products against Gram-positive bacteria but showed no activity against P. aeruginosa. The length of the fatty acid was shown to be important for optimal biological activity, while the hybridisation at the α,β position and branching within the fatty acyl chain had only subtle effects on activity.
Synthesis of α,β-unsaturated aldehydes as potential substrates for bacterial luciferases
Brodl, Eveline,Ivkovic, Jakov,Tabib, Chaitanya R.,Breinbauer, Rolf,Macheroux, Peter
, p. 1487 - 1495 (2017/02/18)
Bacterial luciferase catalyzes the monooxygenation of long-chain aldehydes such as tetradecanal to the corresponding acid accompanied by light emission with a maximum at 490?nm. In this study even numbered aldehydes with eight, ten, twelve and fourteen carbon atoms were compared with analogs having a double bond at the α,β-position. These α,β-unsaturated aldehydes were synthesized in three steps and were examined as potential substrates in vitro. The luciferase of Photobacterium leiognathi was found to convert these analogs and showed a reduced but significant bioluminescence activity compared to tetradecanal. This study showed the trend that aldehydes, both saturated and unsaturated, with longer chain lengths had higher activity in terms of bioluminescence than shorter chain lengths. The maximal light intensity of (E)-tetradec-2-enal was approximately half with luciferase of P. leiognathi, compared to tetradecanal. Luciferases of Vibrio harveyi and Aliivibrio fisheri accepted these newly synthesized substrates but light emission dropped drastically compared to saturated aldehydes. The onset and the decay rate of bioluminescence were much slower, when using unsaturated substrates, indicating a kinetic effect. As a result the duration of the light emission is doubled. These results suggest that the substrate scope of bacterial luciferases is broader than previously reported.
Solvent-free, one-pot synthesis of α,β-unsaturated esters in the presence of a C3-symmetric arsine
Wang, Changqing,Yang, Liu,Zhou, Rong,Mei, Guangquan
supporting information, p. 1074 - 1079 (2016/07/16)
An efficient synthesis of α, β-unsaturated esters is achieved via a one-pot reaction in the presence of a C3-symmetric arsine. The key advantages are the short reaction time, simple workup, mild reaction conditions, and high yields.
Stereoselective syntheses of (-)-tetrahydrolipstatin via Prins cyclisations
Yadav,Reddy, M. Sridhar,Prasad
, p. 4995 - 4998 (2007/10/03)
Stereoselective syntheses of (-)-tetrahydrolipstatin have been achieved via two divergent approaches through Prins cyclisations as the key steps. PCC mediated oxidative cleavage, Frater alkylation, Keck allylation, Sharpless asymmetric epoxidation and allylic cleavage were the other key steps employed.
Chemistry and biology of khafrefungin. Large-scale synthesis, design, and structure-activity relationship of khafrefungin, an antifungal agent
Nakamura, Masayuki,Mori, Yuichiro,Okuyama, Kennichi,Tanikawa, Kunihiro,Yasuda, Satoshi,Kanada, Kentaro,Kobayashi, Shu
, p. 3362 - 3376 (2007/10/03)
Large-scale synthesis, design, and structure-activity relationships of khafrefungin are reported. Khafrefungin is an antifungal agent that inhibits inositol phosphorylceramide (IPC) synthase, a enzyme involved in fungal sphingolipid biosynthesis. Unlike o
Synthesis of new trans double-bond sphingolipid analogues: Δ4,6 and Δ6 ceramides
Chun, Jiong,Li, Guoqing,Byun, Hoe-Sup,Bittman, Robert
, p. 2600 - 2605 (2007/10/03)
Unsaturation was introduced at Δ4,6 and Δ6 of the sphingoid chain of naturally occurring ceramide 1 via a β-keto sulfoxide (12) and sulfone (18) derived from N-Boc-L-serine methyl ester acetonide (9), affording two novel ceramide analogues, (2S,3R)-2-octanoylamidooctadeca-(4E,6E)-diene-1,3diol (2) and (2S,3R)-2-octanoylamidooctadec-(6E)-ene-1,3-diol (3). After C-alkylation of 12 with (E)1-bromo-2-tetradecene (8), a trans double bond was installed by elimination of PhS(O)H, providing conjugated dienone oxazolidine 13. Reaction of 18 with 8, followed by desulfonation (Al(Hg)), afforded keto-oxazolidine 20, which bears a (E)-Δ6 double bond. The syntheses of analogues 2 and 3 from ketones 13 and 20, respectively, were completed by the following sequence of reactions: diastereoselective reduction (NaBH4/CeCl3 or DIBAL-H), hydrolysis of the oxazolidine ring, liberation of the amino group, and installation of the N-amide group.
Syntheses of the Macrocyclic Spermine Alkaloids (+/-)-Budmunchiamine A-C
Popaj, Kasim,Hesse, Manfred
, p. 180 - 186 (2007/10/03)
The syntheses of four macrocyclic spermine alkaloids, (+/-)-budmunchiamine A-C (1a-c) and (+/-)-budmunchiamine L4 (1), were accomplished by Michael addition of spermine to the α,β-unsaturated esters 3a-d, followed by cyclization of the resulting α,ω-tetraamino esters 4a-d with triethoxyantimony; N-methylation of the amino lactams 6a-c yielded the budmunchiamines A-C (1a-c).
