An alternative stereoselective synthesis of (<i>R</i>)‐ and (<i>S</i>)‐Rosaphen® via asymmetric catalytic hydrogenation

Matteoli, Ugo; Beghetto, Valentina; Scrivanti, Alberto; Aversa, Manuela; Bertoldini, Matteo; Bovo, S

doi:10.1002/chir.20989

Cited by 22 publications

(13 citation statements)

References 59 publications

(60 reference statements)

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“…Unless otherwise reported, DMT-Ams(ClO 4 ) were synthesized from CDMT with the corresponding tertiary amine and NaOCl 4 according to the synthetic procedure reported in the literature [43,53]. All products, 3a-3i, were characterized and purity was confirmed by comparison to the literature data [64][65][66][67][68][69][70] 3.2.…”

Section: Methodsmentioning

confidence: 99%

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Sustainable Triazine-Based Dehydro-Condensation Agents for Amide Synthesis

et al. 2021

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Conventional methods employed today for the synthesis of amides often lack of economic and environmental sustainability. Triazine-derived quaternary ammonium salts, e.g., 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM(Cl)), emerged as promising dehydro-condensation agents for amide synthesis, although suffering of limited stability and high costs. In the present work, a simple protocol for the synthesis of amides mediated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and a tert-amine has been described and data are compared to DMTMM(Cl) and other CDMT-derived quaternary ammonium salts (DMT-Ams(X), X: Cl− or ClO4−). Different tert-amines (Ams) were tested for the synthesis of various DMT-Ams(Cl), but only DMTMM(Cl) could be isolated and employed for dehydro-condensation reactions, while all CDMT/tert-amine systems tested were efficient as dehydro-condensation agents. Interestingly, in best reaction conditions, CDMT and 1,4-dimethylpiperazine gave N-phenethyl benzamide in 93% yield in 15 min, with up to half the amount of tert-amine consumption. The efficiency of CDMT/tert-amine was further compared to more stable triazine quaternary ammonium salts having a perchlorate counter anion (DMT-Ams(ClO4)). Overall CDMT/tert-amine systems appear to be a viable and more economical alternative to most dehydro-condensation agents employed today.

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Section: Methodsmentioning

confidence: 99%

“…Our research group has long been involved in the study of innovative sustainable processes for fine chemistry [51][52][53][54]. Recently, our studies have focused on the development of new dehydro-condensation agents.…”

Section: Introductionmentioning

confidence: 99%

Sustainable Triazine-Based Dehydro-Condensation Agents for Amide Synthesis

et al. 2021

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“…The absolute configuration at C-12 in 7 was tentatively assigned as S based on the comparison of its specific rotation ([α] 24 D −6.0) with those of (R)/(S)-rosaphen ([α] 24 D −13.6 for S and [α] 24 D +12.6 for R). 24,25 The presence of 4-acyl-2-aminoimidazole moieties in strepimidazoles A−G (1−7) can be supported by the HMBC correlation from H-5 to C-6 in the HMBC spectra.…”

Section: ■ Results and Discussionmentioning

confidence: 89%

Strepimidazoles A–G from the Plant Endophytic Streptomyces sp. PKU-EA00015 with Inhibitory Activities against a Plant Pathogenic Fungus

et al. 2020

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Seven new 4-acyl-2-aminoimidazoles, designated strepimidazoles A–G (1–7), were discovered from the endophytic Streptomyces sp. PKU-EA00015 isolated from Salvia miltiorrhiza Bunge, whose dry root “Danshen” is one of the most widely used traditional Chinese medicines. The resonance signals of the 2-aminoimidazole moiety in 1–7 were absent in the NMR spectra due to tautomerization, and the structures of 1–7 were identified after preparation of their acetylation products 1a–7a, respectively. Compounds 1–7 represent a new family of 2-aminoimidazole-containing natural products, enriching the structural diversity of natural products from endophytic origin. Compounds 1–7 showed different degrees of inhibitory activities against the plant pathogenic fungus Verticillium dahliae V991, revealing structure–activity relationships on the acyl moieties. The plant pathogenic fungus V. dahliae has been confirmed to cause serious chlorosis of cultivated S. miltiorrhiza Bunge in China. This study opens the door for further investigation of mutualistic relationships between S. miltiorrhiza Bunge and their endophytic actinomycetes and for possible antifungal agent development for biological control of V. dahliae in the future.

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“…The product was then reduced to (R)-Rosaphen, a fragrance with floral rosy odor. 58 The 3,5-dimethyl-substituted MeO-BIPHEP congener has been used for the preparation of (R)-2-(3chloro-4-methanesulfonyl-phenyl)-3-cyclopentyl propionic acid, the key chiral building block for a GK3 activator, with up to 92% ee (eq 38). Ppm amounts of catalysts were sufficient to achieve this transformation.…”

Section: Asymmetric Hydrogenation Of C=c Double Bonds 2-mentioning

confidence: 99%