Total Synthesis and Structural Revision of Laurefurenynes A and B

Holmes, Michael; Britton, Robert

doi:10.1002/chem.201302352

Cited by 38 publications

(26 citation statements)

References 31 publications

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“…Funjii [11], and their structures were elucidated by spectroscopic studies. Naturally occurring C 15 tetrahydrofuranyl derivatives belong to a wider family of halogenated C 15 -acetogenins isolated from red algae of the species Laurencia [12], the majority of the structures of which have only partially had their relative configurations assigned or still need to be investigated to confirm or correct their reported structures [1,13,14]. The challenging relative configurations of the five-membered rings of compounds 1 – 5 were established by our simple and effective J -based methodology [7].…”

Section: Introductionmentioning

confidence: 99%

Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations

et al. 2014

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Five-membered rings are of particular interest, due to their presence in some of the most common molecules in chemistry and biology. Despite their apparent simplicity, the structural resolution of these rings is complex, due to their inherent conformational flexibility. Here, we describe an application of a recently reported simple and efficient NMR protocol based on the measurement of spin-spin coupling constants to achieve the challenging relative configurations of five new halogenated C15 tetrahydrofuranyl-acetogenins, marilzafurollenes A–D (1–4) and 12-acetoxy-marilzafurenyne (5), isolated from the red alga, Laurencia marilzae. Although DFT chemical shift calculations were used to connect remote stereocenters, the NMR-based approach seems advantageous over computational techniques in this context, as the presence of halogens may interfere with reliable calculations.

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Section: Introductionmentioning

confidence: 99%

Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations

et al. 2014

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“…Hydrolytic kinetic resolution of the terminal epoxide 9 under Jacobsen conditions [8] gave enantiomerically pure epoxide 10 (95 % ee) in 45 % yield. Oxidation of known alcohol 13 [11] under Swern conditions gave an aldehyde, which reacted with the ylide generated from known phosphonium bromide 14 [12a,12b] and KHMDS [potassium bis(trimethylsilyl)amide] to give the desired Z-olefin 15 in 70 % yield over two steps (Z/E = 20:1). [9] Protection of the hydroxy group of 11a as its TBS ether followed by debenzylation by hydrogenolysis (H 2 , 10 % Pd/C) gave alcohol 12 in 89 % yield over two steps.…”

mentioning

confidence: 99%

Total Synthesis of the Anticancer Marine Natural Product Mycalol

2018

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This communication describes a synthetic study of the originally proposed structure of mycalol (1) and the total synthesis of the actual structure of the anticancer marine natural product mycalol (2). The total synthesis of the originally proposed structure of mycalol (1) was targeted by a late‐stage asymmetric dihydroxylation, which resulted in an inseparable mixture of diastereomers. Thus a new strategy was developed for the total synthesis of the revised structure of mycalol (2); all the stereocentres except the C‐2′‐OH were created in an asymmetric fashion by using a Maruoka allylation, a Noyori asymmetric reduction, and an asymmetric alkynylation.

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“…Whereas treatment of 9le with Raney nickel and hydrogen in acetone led merely to hydrogenation of the α,β‐unsaturation (product 24 ), omitting hydrogen and changing the solvent to ethanol afforded 23 as the main product . Additionally, chloride 9ia could be converted to vinyltetrahydrofuran 25 in two simple steps, involving Luche reduction and silver‐mediated S N 2 ring closure (Scheme b) …”

Section: Resultsmentioning

confidence: 99%

Redox‐Neutral Arylations of Vinyl Cation Intermediates

2016

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Hereinw ep resent an ew unifiedc oncept for C À Cb ond formation under redox-neutralc onditions.O ur strategyh inges upon interception of av inyl cation with as ulfoxide resulting in simultaneous C-Ca nd C À Ob ond formation and arylation. A range of structurallyd iverse vinyl cations are generated in situ in the presence of as ulfoxide,r esulting in hydrative arylation, direct arylation of enol triflates andi nterrupted Meyer-Schuster rearrange-ment. Mechanistic investigationss howcase the crucial role played by the fleetingv inyl cation intermediatea nd structural featurest hat lead to its stabilization.Applications of the reactionproductstosynthesis are also presented.

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Total Synthesis and Structural Revision of Laurefurenynes A and B

Cited by 38 publications

References 31 publications

Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations

Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations

Total Synthesis of the Anticancer Marine Natural Product Mycalol

Redox‐Neutral Arylations of Vinyl Cation Intermediates

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