Determination of absolute structure using Bayesian statistics on Bijvoet differences

Hooft, Rob; Straver, Leo; Spek, Anthony L.

doi:10.1107/s0021889807059870

Cited by 696 publications

(638 citation statements)

References 20 publications

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“…However, Bijvoet pair analysis gives the Hooft parameter for this structure as −0.01ð6Þ. The probability (P2) that the handedness has been correctly assigned is 1.000 and "P3 (false)" is 0.2 e-09 (20), indicating that the absolute configuration of 12 is as shown in Scheme 2-i.e., R at C-3. Two other minor compounds were isolated: These proved to be the known fungal metabolite leptosphaerone A 13 (21,22) and its oxidized precursor 14 (which we name leptosphaerdione).…”

Section: Resultsmentioning

confidence: 99%

Genetic, molecular, and biochemical basis of fungal tropolone biosynthesis

Davison

Fahad

Cai

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

159

167

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A gene cluster encoding the biosynthesis of the fungal tropolone stipitatic acid was discovered in Talaromyces stipitatus ( Penicillium stipitatum ) and investigated by targeted gene knockout. A minimum of three genes are required to form the tropolone nucleus: tropA encodes a nonreducing polyketide synthase which releases 3-methylorcinaldehyde; tropB encodes a FAD-dependent monooxygenase which dearomatizes 3-methylorcinaldehyde via hydroxylation at C-3; and tropC encodes a non-heme Fe(II)-dependent dioxygenase which catalyzes the oxidative ring expansion to the tropolone nucleus via hydroxylation of the 3-methyl group. The tropA gene was characterized by heterologous expression in Aspergillus oryzae , whereas tropB and tropC were successfully expressed in Escherichia coli and the purified TropB and TropC proteins converted 3-methylorcinaldehyde to a tropolone in vitro. Finally, knockout of the tropD gene, encoding a cytochrome P450 monooxygenase, indicated its place as the next gene in the pathway, probably responsible for hydroxylation of the 6-methyl group. Comparison of the T. stipitatus tropolone biosynthetic cluster with other known gene clusters allows clarification of important steps during the biosynthesis of other fungal compounds including the xenovulenes, citrinin, sepedonin, sclerotiorin, and asperfuranone.

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Section: Resultsmentioning

confidence: 99%

Genetic, molecular, and biochemical basis of fungal tropolone biosynthesis

Davison

Fahad

Cai

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

159

167

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“…The absolute configurations of 18b, 10a, 11a, 23, 10b, 11b, 10d, 11d could not be determined reliably by refinement of Flack's xparameter, [52] Parsons x-parameter [53] nor Hofft's y-parameter, [54] using the effects of anomalous scattering. For all structures the enantiomer (absolute configuration) has been assigned by reference to an unchanging chiral centre in the synthetic procedure.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Chiral (Indol‐2‐yl)methanamines and Insight into the Stereochemistry Protecting Effects of the 9‐Phenyl‐9‐fluorenyl Protecting Group

et al. 2015

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(2015). Synthesis of chiral 2-indolyl methanamines and insight into the stereochemistry protecting effects of the 9-phenyl-9-fluorenyl protecting group. EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 2015(17) Keywords: Asymmetric synthesis / Amino acids / Chiral pool / Protecting groups Tetrahydro-β-carbolines, a privileged structural feature in natural products and pharmaceutically active compounds, has been the cause for considerable research interest, spanning many decades. Herein is reported the synthesis of the structurally closely related compounds denoted as (indol-2-yl)methanamines, in 99 % ee using amino acid starting materials, coupled with a 9-phenyl-9-fluorenyl (Pf) protect-

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“…The absolute configuration was evaluated using likelihood methods in PLATON. 6,7 Based on the analysis of 1077 Bijvoet pairs (90% coverage), this analysis indicated that the absolute structure had been correctly assigned. The method calculated that the probability that the structure is inverted is smaller than 1 × 10-34.…”

Section: X-ray Crystal Structure Determination Of [(+)-Epi-2b]mentioning

confidence: 99%

Enantioselective synthesis of strobamine and its analogues

Zhang¹,

Abraham²,

Mascarella³

et al. 2010

Arkivoc

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Abstract(2S,5S,8R)-Strobamine (+)-1a was synthesized by adding cinnamoyl cyanide 6a to tropinone 3 lithium enolate generated by treatment of (S,S')-α,α-dimethyldibenzylamide with butyl lithium in the presence of lithium chloride to give (-)-chalcostrobamine (-)-7a, which yielded a one-to-one mixture of (+)-1a and its C-2 epimer (-)-2a on treatment with 2N sulfuric acid. Compounds (+)-1a and (-)-2a could be separated by column chromatography. (-)-Strobamine (-)-1a and (+)-2a were synthesized by a similar set of reactions using the tropinone 3 lithium enolate generated with butyl lithium in the presence of (R,R')-α,α'-dimethyldibenzylamide and lithium chloride. (+)-and (-)-p-Methylstrobamine (+)-and (-)-1b and (+)-and (-)-epi-p-methylstrobamine (+)-and (-)-2b were synthesized by a similar procedure. The absolute configuration of (+)-epi-pmethylstrobamine (+)-2b was determined by X-ray analysis to have the (2S,5R,8S) configuration.

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Determination of absolute structure using Bayesian statistics on Bijvoet differences

Cited by 696 publications

References 20 publications

Genetic, molecular, and biochemical basis of fungal tropolone biosynthesis

Genetic, molecular, and biochemical basis of fungal tropolone biosynthesis

Synthesis of Chiral (Indol‐2‐yl)methanamines and Insight into the Stereochemistry Protecting Effects of the 9‐Phenyl‐9‐fluorenyl Protecting Group

Enantioselective synthesis of strobamine and its analogues

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