Spectroscopic evidence for the existence of a stable acidic ortho-ester

Bladon, Peter; Forrest, Gregory C. H.

doi:10.1039/c19660000481

Cited by 5 publications

(4 citation statements)

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“…14, 1981 a similar analysis for 20 yields a value almost 103 times greater than ^HjO•36 If this mechanism is correct, the solvent isotope effect on & should be almost the same as on the because the recombination of ' with H30+…”

mentioning

confidence: 91%

Direct observation of simple tetrahedral intermediates

Capon¹,

Ghosh²,

Grieve³

1981

Acc. Chem. Res.

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the stability of the OHat the active site is increased even more by long-range hydrogen-bonding interactions between the active (nucleophilic) H20 and components of what has been termed the "water chain" in the active site, indicating again the importance of residues around but not in the active site.Quantum and molecular mechanical calculations have thus provided insights into rate-enhancing factors in enzyme catalysis. Long-range electrostatic and hydrogen-bonding effects are crucial. It will be of interest to investigate these in a systematic manner to discover where the major portion of electrostatic stabilization energy in charge separation processes is centered. It will be further desirable to develop methods to calculate

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mentioning

confidence: 91%

Direct observation of simple tetrahedral intermediates

Capon¹,

Ghosh²,

Grieve³

1981

Acc. Chem. Res.

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“…(7) Preparation of polycyclic ortho esters and hydrogen ortho esters by acylation of diols and triols [164][165][166][167][168][169][170].…”

Section: B Reduction Reactions Involving the Alkoxy Substituents Of mentioning

confidence: 99%

Ortho Esters

Sandler¹

1986

Organic Functional Group Preparations

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“…Given that enterocin D was only formed from solutions containing TFA or samples that were previously in contact with TFA, we hypothesized that enterocin D may be the 2- O -TFA or 8- O -TFA ester of 2 or indeed the 2,8- O -TFA hemiorthoester ( 7 ). While hemiorthoesters are generally only observed as transient reaction intermediates, the presence of a strongly electron-withdrawing group, such as CF 3 , can impart sufficient stability to allow both isolation and spectroscopic characterization , and even single-crystal X-ray diffraction analysis . The formation of the TFA hemiorthoester of 2 would explain the deshielding of both C-2 and C-8, the absence of signals for 2-OH and 8-OH, and the apparent coelution of enterocins C and D, as contact with water would readily hydrolyze 7 back to 2 .…”

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confidence: 99%

Rechoreographing Enterocin’s Ballet of Isomers: Structure Revision of Enterocins C, D, and F

et al. 2020

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The tricyclic scaffold of the bacterial polyketide enterocin was recently shown to undergo stereodiversification through a series of abiotic isomerizations, described metaphorically as a “ballet of isomers”. However, some confusion remains regarding the exact nature of these interconversions, with two independent reports proposing different reaction mechanisms and intermediates. Herein, we have rechoreographed enterocin’s ballet of isomers to provide a unified mechanism and revised the structures reported for enterocins C, D, and F.

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Spectroscopic evidence for the existence of a stable acidic ortho-ester

Cited by 5 publications

References 0 publications

Direct observation of simple tetrahedral intermediates

Direct observation of simple tetrahedral intermediates

Ortho Esters

Rechoreographing Enterocin’s Ballet of Isomers: Structure Revision of Enterocins C, D, and F

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