Stereoselective conversion of keto groups into methyl vinyl quaternary carbon centers

Buckwalter, Brian L.; Burfitt, Ivor R.; Felkin, Hugh; Joly-Goudket, Monique; Naemura, Kōichirō; Salomon, Mary F.; Wenkert, Ernest; Wovkulich, Peter M.

doi:10.1021/ja00488a030

Cited by 47 publications

(26 citation statements)

References 5 publications

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“…For the same reasons, the use of compound 7 , led to the obtention of the enantiomer of van Wyk’s product. In addition, our NMR data are also in agreement with the structure [27].…”

Section: Resultssupporting

confidence: 87%

New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity

et al. 2015

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Abstract:We report herein the synthesis of six diterpene derivatives, three of which are new, generated through known organic chemistry reactions that allowed structural modification of the existing natural products kaurenoic acid (1) and copalic acid (2). The new compounds were fully characterized using high resolution mass spectrometry, infrared spectroscopy, 1 H-and 13 C-NMR experiments. We also report the evaluation of the anti-tuberculosis potential for all compounds, which showed some promising results for Micobacterium tuberculosis inhibition. Moreover, the toxicity for each of the most active compounds was also assessed.

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“…For the same reasons, the use of compound 7 , led to the obtention of the enantiomer of van Wyk’s product. In addition, our NMR data are also in agreement with the structure [27].…”

Section: Resultssupporting

confidence: 87%

New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity

et al. 2015

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“…Finally, the carbon chemical shifts of the vinyl and methyl groups (151.5/108.5 and 23.03 for C15/C16 and C17, respectively) are consistent with an axial methyl group and equatorial vinyl, and the stereochemical configuration as 13- epi -dolabradiene. 90 Polarimetric analysis yielded the optical rotation of [α]D + 86.25° (c. 0.0016, dimethyl sulfoxide [DMSO]), in consonance with the earlier reported value of [α]D + 86, 88 while the optical rotation for dolabradiene was reported as [α]D −70. 88 This configuration is consistent with the earlier described stereochemistry of merilactone.…”

Section: Resultssupporting

confidence: 83%

Genome assembly of Chiococca alba uncovers key enzymes involved in the biosynthesis of unusual terpenoids

Lau¹,

Bhat²,

Hamilton³

et al. 2020

DNA Research

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Abstract Chiococca alba (L.) Hitchc. (snowberry), a member of the Rubiaceae, has been used as a folk remedy for a range of health issues including inflammation and rheumatism and produces a wealth of specialized metabolites including terpenes, alkaloids, and flavonoids. We generated a 558 Mb draft genome assembly for snowberry which encodes 28,707 high confidence genes. Comparative analyses with other angiosperm genomes revealed enrichment in snowberry of lineage-specific genes involved in specialized metabolism. Synteny between snowberry and Coffea canepehora Pierre ex A. Froehner (coffee) was evident, including the chromosomal region encoding caffeine biosynthesis in coffee, albeit syntelogs of N-methyltransferase were absent in snowberry. A total of 27 putative terpene synthase genes were identified, including 10 that encode diterpene synthases. Functional validation of a subset of putative terpene synthases revealed that combinations of diterpene synthases yielded access to products of both general and specialized metabolism. Specifically, we identified plausible intermediates in the biosynthesis of merilactone and ribenone, structurally unique antimicrobial diterpene natural products. Access to the C. alba genome will enable additional characterization of biosynthetic pathways responsible for health-promoting compounds in this medicinal species.

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“…Previously, this concept was investigated by using a sequence of reactions, which consists of addition of CH 2 QCHMgBr to 4-tert-butyl-cyclohexanone and a nickel-catalyzed allylic substitution of the resulting allylic alcohol with MeMgBr, producing 4-tert-butyl-1-methyl-1-vinylcyclohexane. 1 Although the stereoselectivity is quite high (ca. 95%), the reaction suffers from somewhat low regioselectivity (81-86%), indicating difficulty in controlling the reaction site of the p-allylnickel intermediates.…”

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confidence: 99%

“…2,3 Recently, we found highly regio-and stereoselective substitution of allylic picolinates with classes of organocopper reagents to afford the anti S N 2 0 products 2 (Scheme 1, eqn (1)). 4 With this substitution in mind, we envisioned a sequence of reactions shown in eqn (2) though the regioselectivity at the g carbon over the a carbon in the allylation of picolinates 4 was uncertain as the g and a carbons are, respectively, more and less congested than the substrates examined in eqn (1). Furthermore, the influence of the substituent(s) attached to the cyclohexane ring on stereoselectivity was unprecedented.…”

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confidence: 99%

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Construction of a quaternary carbon at the carbonyl carbon of the cyclohexane ring

et al. 2010

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Stereoselective conversion of keto groups into methyl vinyl quaternary carbon centers

Cited by 47 publications

References 5 publications

New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity

New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity

Genome assembly of Chiococca alba uncovers key enzymes involved in the biosynthesis of unusual terpenoids

Construction of a quaternary carbon at the carbonyl carbon of the cyclohexane ring

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