31706-95-3Relevant academic research and scientific papers
Studies directed toward the synthesis of hedycoropyrans: total synthesis of des-hydroxy (?)-hedycoropyran B (ent-rhoiptelol B)
Kataria, Priyanka,Nomula, Rajesh,Kontham, Ravindar
, p. 444 - 463 (2022/01/20)
A full account of our efforts directed towards the synthesis of the diarylheptanoid-derived natural products hedycoropyrans that led to the total synthesis of ent-rhoiptelol B is described. In this endeavor, we have attempted two distinct synthetic strategies to access hedycoropyrans A and B, which led us to establish a facile synthetic route for des-hydroxy (?)-hedycoropyran B (ent-rhoiptelol B) from simple and readily accessible building blocks of 4-allylanisole and vanillin, employing Sharpless asymmetric epoxidation, CBS reduction, and an intramolecular AgOTf-catalyzed oxa-Michael reaction of suitably functionalized hydroxy-ynone as key transformations. The investigations disclosed herein will provide insights into designing novel synthetic routes for THP-DAH-derived natural products.
Laccase-catalyzed oxidation of allylbenzene derivatives: Towards a green equivalent of ozonolysis
Antoniotti, Sylvain,Blerot, Bernard,Chietera, Giorgiana,Lecourt, Mathilde
supporting information, (2021/10/19)
Laccase-based biocatalytic reactions have been tested with and without mediators and optimized in the oxidation of allylbenzene derivatives, such as methyl eugenol taken as a model substrate. The reaction primarily consisted in the hydroxylation of the propenyl side chain, either upon isomerization of the double bond or not. Two pathways were then observed; oxidation of both allylic alcohol intermediates could either lead to the corresponding α,β-unsaturated carbonyl com-pound, or the corresponding benzaldehyde derivative by oxidative cleavage. Such a process consti-tutes a green equivalent of ozonolysis or other dangerous or waste-generating oxidation reactions. The conversion rate was sensitive to the substitution patterns of the benzenic ring and subsequent electronic effects.
Iridium-Catalyzed Asymmetric Allylic Alkylation of Deconjugated Butyrolactams
Mitra, Sankash,Mukherjee, Santanu
supporting information, p. 3021 - 3026 (2021/05/04)
Compared with the ever-growing list of nonprochiral nucleophiles in Ir-catalyzed asymmetric allylic substitution reactions, prochiral nucleophiles are less studied. We present a new prochiral nucleophile, namely, deconjugated butyrolactam, for Ir-catalyze
[Pd]-Catalyzedpara-selective allylation of phenols: access to 4-[(E)-3-aryl/alkylprop-2-enyl]phenols
Chinnabattigalla, Sreenivasulu,Choudhury, Aditya,Gedu, Satyanarayana
supporting information, p. 8259 - 8263 (2021/10/12)
4-[(E)-3-Arylprop-2-enyl]phenols are omnipresent scaffolds and constitute natural products and biologically significant compounds. Obtusastyrene and obtustyrene are two such phenolic-based natural products isolated fromDalbergia retusa. The development of strategies based on a site-selective allylation, particularly protecting group-free substrates and non-activated coupling agents, is indispensable in organic synthesis. Herein, we present a highly regioselective [Pd]-catalyzedpara-allylation of phenols using simple, inactivated allylic alcohols as allylating coupling partners. Notably, this strategy is successful in open-air and under mild reaction conditions. Besides, the efficacy of the present protocol was demonstrated by the direct synthesis of obtusastyrene and obtustyrene.
Highly efficient kinetic resolution of aryl-alkenyl alcohols by ru-catalyzed hydrogen transfer
Jin, Ming Yu,Tao, Guanyu,Xing, Xiangyou,You, Yipeng
supporting information, (2021/12/24)
No matter through asymmetric reduction of ketones or kinetic resolution of secondary alcohols, enantioselective synthesis of the corresponding secondary alcohols is challenging when the two groups attached to the prochiral or chiral centers are spatially
Allylic and Allenylic Dearomatization of Indoles Promoted by Graphene Oxide by Covalent Grafting Activation Mode
Lombardi, Lorenzo,Bellini, Daniele,Bottoni, Andrea,Calvaresi, Matteo,Monari, Magda,Kovtun, Alessandro,Palermo, Vincenzo,Melucci, Manuela,Bandini, Marco
supporting information, p. 10427 - 10432 (2020/07/24)
The site-selective allylative and allenylative dearomatization of indoles with alcohols was performed under carbocatalytic regime in the presence of graphene oxide (GO, 10 wt percent loading) as the promoter. Metal-free conditions, absence of stoichiometric additive, environmentally friendly conditions (H2O/CH3CN, 55 °C, 6 h), broad substrate scope (33 examples, yield up to 92 percent) and excellent site- and stereoselectivity characterize the present methodology. Moreover, a covalent activation model exerted by GO functionalities was corroborated by spectroscopic, experimental and computational evidences. Recovering and regeneration of the GO catalyst through simple acidic treatment was also documented.
Asymmetric Synthesis of γ-Secondary Amino Alcohols via a Borrowing-Hydrogen Cascade
Chang, Xiaoyong,Chen, Fumin,He, Dongxu,Jin, Ming Yu,Pan, Yupeng,Xing, Xiangyou,You, Yipeng
supporting information, p. 7278 - 7283 (2020/10/02)
The borrowing-hydrogen (or hydrogen autotransfer) process, where the catalyst dehydrogenates a substrate and formally transfers the H atom to an unsaturated intermediate, is an atom-efficient and environmentally benign transformation. Described here is an example of an asymmetric borrowing-hydrogen cascade for the formal anti-Markovnikov hydroamination of allyl alcohols to synthesize optically enriched γ-secondary amino alcohols. By exploiting the Ru-(S)-iPrPyme catalyst with minimal stereogenicity, a cascade process including dehydrogenation, conjugate addition, and asymmetric reduction was developed. The mild conditions, functional group tolerance, and broad substrate scope (54 examples) demonstrate the synthetic practicality of the catalytic system.
1,3-Dioxa-[3,3]-sigmatropic Oxo-Rearrangement of Substituted Allylic Carbamates: Scope and Mechanistic Studies
Agirre, Maddalen,Henrion, Sylvain,Rivilla, Ivan,Miranda, José I.,Cossío, Fernando P.,Carboni, Bertrand,Villalgordo, José M.,Carreaux, Fran?ois
, p. 14861 - 14881 (2019/01/04)
An unexpected 1,3-dioxa-[3,3]-sigmatropic rearrangement during the treatment of aryl- and alkenyl-substituted allylic alcohols with activated isocyanates is reported. The reorganization of bonds is highly dependent on the electron density of the aromatic
Isothiourea-Catalysed Acylative Kinetic Resolution of Aryl–Alkenyl (sp2vs. sp2) Substituted Secondary Alcohols
Musolino, Stefania F.,Ojo, O. Stephen,Westwood, Nicholas J.,Taylor, James E.,Smith, Andrew D.
supporting information, p. 18916 - 18922 (2016/12/26)
The non-enzymatic acylative kinetic resolution of challenging aryl–alkenyl (sp2vs. sp2) substituted secondary alcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron-rich or naphthyl aryl substituents in combination with an unsubstituted vinyl substituent providing the highest selectivity (S=2–1980). The use of this protocol for the gram-scale (2.5 g) kinetic resolution of a model aryl–vinyl (sp2vs. sp2) substituted secondary alcohol is demonstrated, giving access to >1 g of each of the product enantiomers both in 99:1 e.r.
The synthesis and analysis of lignin-bound Hibbert ketone structures in technical lignins
Miles-Barrett, Daniel M.,Neal, Andrew R.,Hand, Calum,Montgomery, James R.D.,Panovic, Isabella,Ojo, O. Stephen,Lancefield, Christopher S.,Cordes, David B.,Slawin, Alexandra M.Z.,Lebl, Tomas,Westwood, Nicholas J.
supporting information, p. 10023 - 10030 (2016/11/06)
Understanding the structure of technical lignins resulting from acid-catalysed treatment of lignocellulosic biomass is important for their future applications. Here we report an investigation into the fate of lignin under acidic aqueous organosolv conditions. In particular we examine in detail the formation and reactivity of non-native Hibbert ketone structures found in isolated organosolv lignins from both Douglas fir and beech woods. Through the use of model compounds combined with HSQC, HMBC and HSQC-TOCSY NMR experiments we demonstrate that, depending on the lignin source, both S and G lignin-bound Hibbert ketone units can be present. We also show that these units can serve as a source of novel mono-aromatic compounds following an additional lignin depolymerisation reaction.
