Asymmetric Synthesis. In their Research Article (e202315872), Maria Besora, Montserrat Diéguez et al. report fast and highly selective Ir‐catalysts for the asymmetric hydrogenation of ...tetrasubstituted acyclic enones.
Strategies for the synthesis of axially chiral compounds featuring a N−C stereogenic axis with an emphasis in catalytic asymmetric approaches are discussed in this Review article, by Fernández, ...Hornillos and Lassaletta et al. (DOI: 10.1002/chem.202104442). @LassaFdezGroup. #asymmetriccatalysis #axialchirality #atropisomers
Correction and removal of expression of concern for ‘A general and concise asymmetric synthesis of sphingosine, safingol and phytosphingosines via tethered aminohydroxylation’ by Pradeep Kumar, et ...al. , Org. Biomol. Chem. , 2010, 8 , 5074–5086, DOI: 10.1039/C0OB00117A.
Correction for 'Asymmetric synthesis of (−)-solanidine and (−)-tomatidenol' by Yun Wang
et al.
,
Org. Biomol. Chem.
, 2020,
18
, 3169-3176, DOI:
10.1039/D0OB00457J
.
Both the enantiomers of racemic 4-O-tosyl-6-O-benzyl-myo-inositol-1,3,5-orthoformate (2) were isolated by preferential crystallization and used to synthesize several enantiomeric myo-inositol ...derivatives - natural ononitol, natural laminitol, precursors for myo-inositol phosphates and an oxabicyclo 2.2.1 heptane derivative. This work demonstrates the potential of the enantiomeric tosylates D2 and L2 to serve as versatile starting materials for the absolute asymmetric synthesis of inositol derivatives and other natural products from symmetric myo-inositol since no optically active molecular entity was required for the resolution of 2.
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•First absolute asymmetric synthesis of inositol derivatives.•Enantiomeric myo-inositol derivatives as potential chiral pool molecules.•Access to the same enantiomeric inositol derivative from both D- and L-synthons.
The cryptolactones A1, A2, B1, and B2 isolated from a Cryptomyzus sp. aphid were synthesized via the Mukaiyama aldol reaction and olefin metathesis. Their antipodes and derivatives were also ...synthesized by the same strategy to investigate structure-activity relationships. These compounds exhibited cytotoxic activity against human promyelocytic leukemia HL-60 cells with IC50 values of 2.1-42 μM.
Lipoxins (LXs) are endogenously generated eicosanoids with potent bio-actions consistent with attenuation of inflammation. The costly synthesis and metabolic instability of LXs may limit their ...therapeutic potential. Here we report the synthesis and characterization of novel imidazole-/oxazole-containing synthetic-LX-mimetics (sLXms). The key steps of asymmetric synthesis of putative sLXms include a Suzuki reaction and an asymmetric ketone reduction. The effect of the novel compounds on inflammatory responses was assessed using a human monocyte cell line stably expressing a Nuclear Factor Kappa B (NFkB) reporter gene, by investigating downstream cytokine secretion. The potential interaction of the imidazoles/oxazoles with the molecular target of LXs, i.e. G-protein coupled receptor (GPCR) Formyl Peptide Receptor 2 (ALX/FPR2) was investigated using a cell system where ALX/FPR2 is coupled to the Gαq subunit and receptor interaction determined by mobilisation of intracellular calcium. In vivo anti-inflammatory effects were assessed using a murine zymosan-induced peritonitis model. Overall, structure-activity relationship (SAR) studies demonstrated that the (R)-epimer of 6C-dimethyl-imidazole (1R)-11 was the most potent and efficient anti-inflammatory agent, among the ten compounds tested. This molecule significantly attenuated LPS-induced NFkB activity, reduced the release of several pro-inflammatory cytokines and inhibited peritonitis-associated neutrophil infiltration in vivo. The underlying mechanism for those actions appeared to be through FPR2 activation. These data support the therapeutic potential of imidazole-containing sLXms in the context of novel inflammatory regulators.
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•The synthesis of novel sLXms includes Suzuki reaction & asymmetric ketone reduction.•(1R)-11 IMZ is the most potent & efficient anti-inflammatory sLXm here tested.•(1R)-11 attenuated LPS-induced NFkB activity & release of proinflammatory cytokines.•(1R)-11 inhibited peritonitis-associated neutrophil count in vivo.•The underlying mechanism for those actions appears to be through FPR2 activation.
An asymmetric Rh-catalyzed transfer hydrogenation was developed for the conversion of α-enamidophosphonates to α-aminophosphonates (α-APs) using isopropanol as the hydride donor. This methodology is ...amenable to a broad substrate scope. A library of structurally diverse α-APs was synthesized in moderate to good yield and enantiomeric excess, having a methylene moiety at Cβ and aryl, heteroaryl or alkyl side chains.
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The front cover picture illustrates the variety of products accessible through the newly developed asymmetric hydrohydrazonemethylation (HHM). The devised hydroformylation/condensation sequence leads ...to stable and versatile γ‐chiral N’‐substituted aceto‐hydrazones. They can be reduced in one‐pot to the corresponding γ‐chiral N’‐substituted acetohydrazides, and after deprotection, to β‐chiral hydrazines. They can be also reduced and hydrogenolysed to the β‐chiral primary amines or serve as substrates for diastereoselective C−C coupling. The high enantioselectivity reached for all product types makes the molecular peacock proud of its pluridecorated tail. Details can be found in the communication by Franciò and co‐workers (M. N. Kliemann, S. Teeuwen, C. Weike, G. Franciò, W. Leitner, Adv. Synth. Catal. 2022, 364, 4006–4012; DOI: 10.1002/adsc.202200804).
Abstract
A method for conducting enantioselective bromolactonization reactions of trisubstituted alkenoic acids, using the
C
3
‐symmetric trisimidazoline
1
and 1,3‐dibromo‐5,5‐dimethyl hydantoin as a ...bromine source, has been developed. The process generates chiral δ‐lactones that contain a quaternary carbon. The results of studies probing geometrically different olefins show that (
Z
)‐olefins rather than (
E
)‐olefins are favorable substrates for the process. The method is not only applicable to acyclic olefin reactants but can also be employed to transform cyclic trisubstituted olefins into chiral spirocyclic lactones. Finally, the synthetic utility of the newly developed process is demonstrated by its application to a concise synthesis of tanikolide, an antifungal marine natural product.
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