Carbon-branched carbohydrate chirons: practical access to both enantiomers of 2-C-methyl-ribono-1,4-lactone and 2-C-methyl-arabinonolactone

Booth, Kathrine V.; Cruz, Filipa P. da; Hotchkiss, David J.; Jenkinson, Sarah F.; Jones, Nigel A.; Weymouth‐Wilson, Alexander C.; Clarkson, Robert A.; Heinz, Thomas; Fleet, George W. J.

doi:10.1016/j.tetasy.2008.10.013

Cited by 21 publications

(11 citation statements)

References 51 publications

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“…Therefore, we chose benzyl ether protection for the sugars. The starting material, 2‐ C ‐methyl‐ D ‐ribonolactone ( 4 ), is available in two steps from D ‐glucose 16. Reaction of the lactone 4 with BnBr and NaH in DMF at –10 °C gave key perbenzylated building block 5 in very good yield (89 %) on a multigram scale (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Neutral Nickel Ethylene Oligo‐ and Polymerization Catalysts: Towards Computational Catalyst Prediction and Design

Heyndrickx

Occhipinti

Jensen

2014

Chemistry A European J

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DFT calculations have been used to elucidate the chain termination mechanisms for neutral nickel ethylene oligo- and polymerization catalysts and to rationalize the kind of oligomers and polymers produced by each catalyst. The catalysts studied are the (κ(2)-O,O)-coordinated (1,1,1,5,5,5-hexafluoro-2,4-acetylacetonato)nickel catalyst I, the (κ(2)-P,O)-coordinated SHOP-type nickel catalyst II, the (κ(2)-N,O)-coordinated anilinotropone and salicylaldiminato nickel catalysts III and IV, respectively, and the (κ(2)-P,N)-coordinated phosphinosulfonamide nickel catalyst V. Numerous termination pathways involving β-H elimination and β-H transfer steps have been investigated, and the most probable routes identified. Despite the complexity and multitude of the possible termination pathways, the information most critical to chain termination is contained in only few transition states. In addition, by consideration of the propagation pathway, we have been able to estimate chain lengths and discriminate between oligo- and polymerization catalysts. In agreement with experiment, we found the Gibbs free energy difference between the overall barrier for the most facile propagation and termination pathways to be close to 0 kcal mol(-1) for the ethylene oligomerization catalysts I and V, whereas values of at least 7 kcal mol(-1) in favor of propagation were determined for the polymerization catalysts III and IV. Because of the shared intermediates between the termination and branching pathways, we have been able to identify the preferred cis/trans regiochemistry of β-H elimination and show that a pronounced difference in σ donation of the two bridgehead atoms of the bidentate ligand can suppress hydride formation and thus branching. The degree of rationalization obtained here from a handful of key intermediates and transition states is promising for the use of computational methods in the screening and prediction of new catalysts of the title class.

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Section: Resultsmentioning

confidence: 99%

Neutral Nickel Ethylene Oligo‐ and Polymerization Catalysts: Towards Computational Catalyst Prediction and Design

Heyndrickx

Occhipinti

Jensen

2014

Chemistry A European J

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“…Though the route is feasible, indeed it is hard to be carried out. 19 Our method enabled the efficient synthesis of 4, which was an excellent material for the preparation of 3 by removing the benzoyl protecting groups with K 2 CO 3 , and 13 by chloridization with sulfoxide chloride. With respect to the stereoselective synthesis of diastereomer 12, at present no pleasurable method is available.…”

Section: Dmfmentioning

confidence: 98%

A neighboring group participation strategy: facile synthesis of 3,5-di-O-benzoyl-2-C-methyl-d-arabino-γ-lactone

Xie

Zhang²,

Tian³

et al. 2015

Tetrahedron Letters

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“…For branched iminosugars, see: Hå kansson et al (2007Hå kansson et al ( , 2008; Asano et al (2000); da Cruz et al (2011); Best et al (2010) and for branched sugars, see: Booth et al (2008Booth et al ( , 2009; da ; Hotchkiss et al (2006Hotchkiss et al ( , 2007; Jenkinson et al (2007); Jones et al (2007Jones et al ( , 2008; Rao et al (2008). For conformations of related 1,5-lactones, see: Baird et al (1987); Booth et al (2007a,b); Bruce et al (1990); Punzo et al (2005Punzo et al ( , 2006; Dai et al (2010).…”

Section: Related Literaturementioning

confidence: 99%

6-Deoxy-3,4-O-isopropylidene-2-C-methyl-L-galactono-1,5-lactone

et al. 2011

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X-ray crystallography unequivocally confirmed the stereochemistry of the 2-C-methyl group in the title molecule, C10H16O5, in which the 1,5-lactone ring exists in a boat conformation. The absolute stereochemistry was determined by the use of d-ribose in the synthesis. The crystal exists as O—H⋯O hydrogen bonded chains of molecules running parallel to the a axis with each molecule acting as a donor and acceptor for one hydrogen bond.

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Carbon-branched carbohydrate chirons: practical access to both enantiomers of 2-C-methyl-ribono-1,4-lactone and 2-C-methyl-arabinonolactone

Cited by 21 publications

References 51 publications

Neutral Nickel Ethylene Oligo‐ and Polymerization Catalysts: Towards Computational Catalyst Prediction and Design

Neutral Nickel Ethylene Oligo‐ and Polymerization Catalysts: Towards Computational Catalyst Prediction and Design

A neighboring group participation strategy: facile synthesis of 3,5-di-O-benzoyl-2-C-methyl-d-arabino-γ-lactone

6-Deoxy-3,4-O-isopropylidene-2-C-methyl-L-galactono-1,5-lactone

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