Stereocontrolled total synthesis of (+)-concanamycin F: the strategic use of boron-mediated aldol reactions of chiral ketones

Paterson, Ian; Doughty, Victoria A.; McLeod, Malcolm D.; Trieselmann, Thomas

doi:10.1016/j.tet.2011.09.012

Cited by 30 publications

(13 citation statements)

References 81 publications

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“…To further test the synthetic utility of this methodology, we applied our reaction conditions to more challenging acyclic substrates using the 2-butanone 13 derived sulfinimine ( 1c ) ( Scheme 3 ). This substrate clearly possesses two possible sites for deprotonation: at the kinetically favored methyl carbon and the thermodynamically favored methylene.…”

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confidence: 99%

Stereoselective Installation of Five Contiguous Stereogenic Centers in a Double Aldol–Tishchenko Cascade and Evaluation of the Key Transition State through DFT Calculation

et al. 2021

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The stereoselective formation of 5 contiguous chiral centers in a single pot reaction is demonstrated using an aldol, aldol–Tishchenko reaction of N - tert -butyl sulfinimines. One diastereoisomer (from 32 possibilities) predominates, and a series of cyclic and acyclic 3-amino-1,5-diol derivatives are synthesized in good yields (up to 80%) and excellent diastereoselectivities (up to >98:2 dr). Investigations support two reversible aldol steps, and multiple intermediates which are funnelled through a remarkably selective, irreversible, Tishchenko reduction, in a Curtin–Hammett phenomenon. DFT calculations using a disolvated (THF) model reveal the factors controlling stereoselectivity in the final irreversible Tishchenko step.

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confidence: 99%

Stereoselective Installation of Five Contiguous Stereogenic Centers in a Double Aldol–Tishchenko Cascade and Evaluation of the Key Transition State through DFT Calculation

et al. 2021

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“…Chiral ketones bearing a stereogenic center at the α- or β-position are important compounds in organic synthesis. 1 A few reported methods to access optically active ketones include alkylation using auxiliaries, 2 catalytic asymmetric alkylation, 3 enantioselective Michael addition to unsaturated ketones, 4 or asymmetric conjugate reduction of enones. 5 However, all of the routes listed above to synthesize α- and β-chiral ketones face limitations, such as the challenge of installing/removing auxiliaries, high catalyst loading, or the use of sensitive reagents.…”

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confidence: 99%

Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones

et al. 2020

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Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir–N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.

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“…Posteriormente, foram relatadas as concanamicinas B e C, isoladas de uma linhagem de Streptomyces sp. ; e concanamicina F (KINASHI et al 1984;PATERSON et al 2011). São modificadas por ligações no grupo hidroxila de C23 da fração do anel hemicetal e, dependendo do substituinte, será A, B, C ou F (HAYDOCK et al 2005).…”

Section: B) Concanamicinasunclassified

Streptomyces spp.associadas à sarna da batata

Destéfano¹,

Vitor²,

Corrêa³

et al. 2021

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A sarna da batata, de ocorrência generalizada nas principais regiões produtoras do Brasil e do mundo, é considerada como uma das doenças bacterianas mais importantes que afetam a cultura. Sua incidência vem aumentando, tornando-se um fator limitante na produção da batata no Brasil. A sarna é causada por diferentes espécies do gênero Streptomyces, sendo S. scabiei a espécie mais amplamente distribuída. Os sintomas se caracterizam por lesões superficiais ou profundas que podem afetar toda a superfície do tubérculo, acarretando diminuição do seu valor comercial e até mesmo impedindo a sua comercialização. Os mecanismos de patogenicidade de Streptomyces são considerados altamente evoluídos, e diferentes fatores de patogenicidade estão envolvidos nos processos de penetração, colonização e evasão do sistema de defesa da planta, como a fitotoxina taxtomina A, a proteína necrogênica Nec1 e a enzima tomatinase. Entretanto, algumas espécies fitopatogênicas causadoras da sarna não produzem taxtomina, nem a proteína Nec1, indicando que outras vias metabólicas estão envolvidas na patogenicidade dessas espécies. Considerando os fatores favoráveis ao desenvolvimento da doença, diferentes estratégias de controle podem ser adotadas, a fim de se reduzir a incidência e severidade da sarna. Medidas de controle como plantio de cultivares resistentes, certificação de batata-semente, tratamento dos tubérculos antes do plantio e controle químico ou biológico têm sido empregadas. Entretanto, ainda não há um método com total eficácia. Nesta revisão, serão apresentados e discutidos aspectos relevantes sobre o histórico da sarna da batata, etiologia, ciclo de vida do patógeno, distribuição mundial, determinantes de patogenicidade, medidas de manejo e técnicas de identificação do agente causal.

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Stereocontrolled total synthesis of (+)-concanamycin F: the strategic use of boron-mediated aldol reactions of chiral ketones

Cited by 30 publications

References 81 publications

Stereoselective Installation of Five Contiguous Stereogenic Centers in a Double Aldol–Tishchenko Cascade and Evaluation of the Key Transition State through DFT Calculation

Stereoselective Installation of Five Contiguous Stereogenic Centers in a Double Aldol–Tishchenko Cascade and Evaluation of the Key Transition State through DFT Calculation

Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones

Streptomyces spp.associadas à sarna da batata

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