Steric acceleration of lactonization reaction: an analysis of "stereopopulation control"

DANFORTH, CLAUDIA; Nicholson, Allen W.; James, John C.; Loudon, G. Marc

doi:10.1021/ja00430a044

Cited by 34 publications

(21 citation statements)

References 10 publications

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“…The trimethyl lock facilitates the cyclization reaction entropically through conformational restrictions and enthalpically through a ground state steric strain relief upon cyclization, which is consistent with what has been suggested and discussed extensively (1,3,5,13,14,21,22,(25)(26)(27)(28)(29). We realize that the bending of a quinone carbonyl group out of the plane is relatively easy when compared with an aromatic system.…”

Section: Discussionsupporting

confidence: 87%

Structural Analysis of a Facile Lactonization System Facilitated by a “Trimethyl Lock”

Wang

Nicolaou

Liu

et al. 1996

Bioorganic Chemistry

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Section: Discussionsupporting

confidence: 87%

Structural Analysis of a Facile Lactonization System Facilitated by a “Trimethyl Lock”

Wang

Nicolaou

Liu

et al. 1996

Bioorganic Chemistry

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“…This work [53,54] disproves the former concept of stereopopulation control, suggested by Milstien and Cohen [55], according to which the entropy effect dominates.…”

Section: -Acylpropionic Acids and Substitutedsupporting

confidence: 72%

“…Recently it was shown experimentally [53], and corroborated by force field calculations [54], that the dominant role of rate enhancement of 3-(2-hydroxyphenyl)propionic acid lactonization by methyl substituents in the chain, and in the 3-and 6-positions of the benzene ring, is ground state strain, i.e., an enthalpy effect. This work [53,54] disproves the former concept of stereopopulation control, suggested by Milstien and Cohen [55], according to which the entropy effect dominates.…”

Section: -Acylpropionic Acids and Substitutedmentioning

confidence: 85%

“…Either the open isomers of hydrazides (56A) or the mixtures of bo~h isomers (56 A) + (56B) are formed in the reactions of chloride (53) with N, N -dialkylhydrazines [217]. The recrystallization of hydrazides (56A) from alcohols results in an isomerization (56A) -+ (56B), obviously due to the presence of an NRR group in the molecule, which in boiling alcohol acts…”

Section: (2-phenyl-i3-indanedione-2-yl)acetamides and Hydrazidesmentioning

confidence: 99%

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Intramolecular Reversible Addition Reactions to the C=O Group

Valters¹,

Flitsch

1985

Ring-Chain Tautomerism

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“…Dehydrogenation of 1-sec-hydroxyl group of 1-hydro-1,1a-dihydroxy-9-fluorenone would yield a b-diketonetype compound whose hydrolysis at the C9-C1a bond would give 2Ј-carboxy-2,3-dihydroxybiphenyl. While 8-hydroxy-3,4-benzocoumarin was identified as a metabolite of FN, this compound is in fact the d-lactone of 2Ј-carboxy-2,3-dihydroxybiphenyl and could be formed as a result of a reversible dehydration reaction similar to that described for 8-hydroxy-naphthalene-1-acetic acid (Danforth et al, 1976). meta Cleavage of 2Ј-carboxy-2,3-dihydroxybiphenyl at C1-C2 bond and subsequent hydrolysis result in the formation of phthalic acid and 2-hydroxypenta-2,4-dienoic acid as shown in Fig.…”

Section: -Fluorenone Amentioning

confidence: 83%

Bacterial degradation of aromatic compounds via angular dioxygenation.

Nojiri

Habe

Omori

2001

J. Gen. Appl. Microbiol.

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Dioxygenation is one of the important initial reactions of the bacterial degradation of various aromatic compounds. Aromatic compounds, such as biphenyl, toluene, and naphthalene, are dioxygenated at lateral positions of the aromatic ring resulting in the formation of cis-dihydrodiol. This "normal" type of dioxygenation is termed lateral dioxygenation. On the other hand, the analysis of the bacterial degradation of fluorene (FN) analogues, such as 9-fluorenone, dibenzofuran (DF), carbazole (CAR), and dibenzothiophene (DBT)-sulfone, and DF-related diaryl ether compounds, dibenzo-p-dioxin (DD) and diphenyl ether (DE), revealed the presence of the novel mode of dioxygenation reaction for aromatic nucleus, generally termed angular dioxygenation. In this atypical dioxygenation, the carbon bonded to the carbonyl group in 9-fluorenone or to heteroatoms in the other compounds, and the adjacent carbon in the aromatic ring are both oxidized. Angular dioxygenation of DF, CAR, DBT-sulfone, DD, and DE produces the chemically unstable hemiacetal-like intermediates, which are spontaneously converted to 2,2,3-trihydroxybiphenyl, 2-aminobiphenyl-2,3-diol, 2,3-dihydroxybiphenyl-2-sulfinate, 2,2,3-trihydroxydiphenyl ether, and phenol and catechol, respectively. Thus, angular dioxygenation for these compounds results in the cleavage of the three-ring structure or DE structure. The angular dioxygenation product of 9-fluorenone, 1-hydro-1,1a-dihydroxy-9-fluorenone is a chemically stable cis-diol, and is enzymatically transformed to 2-carboxy-2,3-dihydroxybiphenyl. 2-Substituted 2,3-dihydroxybiphenyls formed by angular dioxygenation of FN analogues are degraded to monocyclic aromatic compounds by meta cleavage and hydrolysis. Thus, after the novel angular dioxygenation, subsequent degradation pathways are homologous to the corresponding part of that of biphenyl. Compared to the bacterial strains capable of catalyzing lateral dioxygenation, few bacteria having angular dioxygenase have been reported. Only a few degradation pathways, CARdegradation pathway of Pseudomonas resinovorans strain CA10, DF/DD-degradation pathway of Sphingomonas wittichii strain RW1, DF/DD/FN-degradation pathway of Terrabacter sp. strain DBF63, and carboxylated DE-degradation pathway of P. pseudoalcaligenes strain POB310, have been investigated at the gene level. As a result of the phylogenetic analysis and the comparison of substrate specificity of angular dioxygenase, it is suggested that this atypical mode of dioxygenation is one of the oxygenation reactions originating from the relaxed substrate specificity of the Rieske nonheme iron oxygenase superfamily. Genetic characterization of the degradation pathways of these compounds suggests the possibility that the respective genetic elements constituting the entire catabolic pathway have been recruited from various other bacteria and/or other genetic loci, and that these pathways have not evolutionary matured.

show abstract

Steric acceleration of lactonization reaction: an analysis of "stereopopulation control"

Cited by 34 publications

References 10 publications

Structural Analysis of a Facile Lactonization System Facilitated by a “Trimethyl Lock”

Structural Analysis of a Facile Lactonization System Facilitated by a “Trimethyl Lock”

Intramolecular Reversible Addition Reactions to the C=O Group

Bacterial degradation of aromatic compounds via angular dioxygenation.

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