Total Synthesis and Structural Revision of Monocillin VII

Mallampudi, N. Arjunreddy; Srinivas, B.; Reddy, Jithender G.; Mohapatra, Debendra K.

doi:10.1021/acs.orglett.9b02075

Cited by 12 publications

(4 citation statements)

References 73 publications

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“…SC0924 79 which has antitumor activities (Scheme 40). 80 Treatment of lactone 67 with Ph 3 PAuCl/AgOTf in dioxane/ H 2 O delightfully gave β-ketone 68 with total β-regioselectivity in an excellent yield of 84%. The intramolecular assistance of the lactone function for the hydration reaction plays a key role in the achieved regioselectivity.…”

Section: Hydration Of Alkynes Directed By An Ester Functionmentioning

confidence: 99%

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

et al. 2023

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Water addition on an unsymmetrical internal alkyne has significance in organic chemistry and has stimulated challenging approaches to access a highly regioselective process. Hydration or formal hydration is presented according to the type of internal alkyne. Methods for electron-rich and -poor diarylalkynes followed by those adapted to arylalkylalkynes are presented. Regioselective hydration reactions of unsymmetrical propargylic and homopropargylic derivatives are then discussed, followed by regioselective aspects of the hydration of internal alkynes directed by carbonyl groups. The following section examines the hydration alkynes linked to CF 3 , esters, ketones, and heteroatoms as haloalkynes, alkynylphosphonates, ynamides, and others. At the end of this section, we report some recent examples of hydration reactions where the alkyne triple bond is connected to an electron-withdrawing group as an ester or a ketone. Reactions are presented, discussed, and illustrated in each of these items through various representative examples. The mechanistic hypotheses explaining the origin of the regioselectivity in the hydration reactions are discussed. This review of recent advances in the regioselective hydration of internal unsymmetrical alkynes (from 2007 until the present) aims to update the current body of knowledge and aid researchers working in this field.

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Section: Hydration Of Alkynes Directed By An Ester Functionmentioning

confidence: 99%

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

et al. 2023

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“…The synthesis of fragment 9 commenced from an advanced intermediate trans -2,6-disubstituted dihydropyran 12 which was synthesized in turn from a known chiral epoxide 13 12 (which was prepared from readily available starting material 3-buten-1-ol in three-step sequence, p -methoxybenzylation with PMB chloride, epoxidation with m CPBA followed by Jacobsen’s hydrolytic kinetic resolution (HKR) 13 using ( S , S )-Jacobsen catalyst in 43% yield and 98% ee (determined by chiral HPLC)) using a three-step protocol developed previously by our group in a 99:1 diastereomeric ratio. 11a d Next, following Jin’s one-step dihydroxylation–oxidation protocol, 14 terminal olefin was selectively oxidized to aldehyde followed by reduction with NaBH 4 in MeOH at 0 °C, which furnished the corresponding alcohol 14 in 78% yield over two steps. The alcohol 14 was protected with TBSCl in the presence of imidazole and a catalytic amount of DMAP in CH 2 Cl 2 at 0 °C to give compound 15 in 96% yield.…”

Section: Table 1 Screening Of Dihydroxylation Reaction ...mentioning

confidence: 99%

Asymmetric Total Synthesis of (2E)-Macrolactin 3

Mohapatra

Reddy

Choudhury

et al. 2022

Synlett

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Asymmetric total synthesis of (2E)-macrolactin 3 has been accomplished in a highly convergent manner utilizing our earlier developed tandem isomerization followed by C-O and C-C bond-forming Sharpless asymmetric dihydroxylation, and a late-stage intramolecular Heck coupling reaction. Comparison of the NMR spectra of the coupled product and thorough analysis of the 2D NMR data of the final compound led to the conclusion that the Z-double bond at C2 was isomerized during the coupling reaction.

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“…The structure–activity relationships analysis indicated that the acetoxy and acetonide groups at C5′–C6′ had positive effects on the antiplasmodial activity (Zhang et al 2017 ). Recently, total syntheses of paecilomycins E (Reddy et al 2019 ) and F, cochliomycin C, 6-epi-cochliomycin C (Kadari et al 2018 ), monocillin VII (Mallampudi et al 2019 ), 5′-hydroxyzearalenone, 5′β-hydroxyzearalenone (Thiraporn et al 2017 ), L-783290, L-783277 (Chakraborty et al 2020 ), paecilomycin B, 6′-epi-paecilomycin B (Ohba and Nakata 2018 ), zeaenol, and 7-epi-zeaenol (Doda et al 2019 ; Mohapatra et al 2014 ) were accomplished and reported. Given their intriguing antifouling and antiplasmodial properties and attractive chemical structures, this family of macrolides has attracted a growing interest in the fields of medicinal chemistry and organic chemistry.…”

Section: Introductionmentioning

confidence: 99%

Structure modification, antialgal, antiplasmodial, and toxic evaluations of a series of new marine-derived 14-membered resorcylic acid lactone derivatives

et al. 2021

Mar Life Sci Technol

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Marine natural products play critical roles in the chemical defense of many marine organisms and are essential, reputable sources of successful drug leads. Sixty-seven 14-membered resorcylic acid lactone derivatives 3–27 and 30–71 of the natural product zeaenol (1) isolated from the marine-derived fungus Cochliobolus lunatus were semisynthesized by chlorination, acylation, esterification, and acetalization in one to three steps. The structures of these new derivatives were established by HRESIMS and NMR techniques. All the compounds (1–71) were evaluated for their antialgal and antiplasmodial activities. Among them, 14 compounds displayed antifouling activities against adhesion of the fouling diatoms. In particular, 9 and 34 exhibited strong and selective inhibitory effects against the diatoms Navicula laevissima and Navicula exigua (EC50 = 6.67 and 8.55 μmol/L), respectively, which were similar in efficacy to those of the positive control SeaNine 211 (EC50 = 2.90 and 9.74 μmol/L). More importantly, 38, 39, and 69–71 showed potent antiplasmodial activities against Plasmodium falciparum with IC50 values ranging from 3.54 to 9.72 μmol/L. Very interestingly, the five antiplasmodial derivatives displayed non-toxicity in the cytotoxicity assays and the zebrafish embryos model, thus, representing potential promising antiplasmodial drug agents. The preliminary structure–activity relationships indicated that biphenyl substituent at C-2, acetonide at positions C-5′ and C-6′, and tri- or tetra-substituted of acyl groups increased the antiplasmodial activity. Therefore, combining evaluation of chemical ecology with pharmacological models will be implemented as a systematic strategy, not only for environmentally friendly antifoulants but also for structurally novel drugs.

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Total Synthesis and Structural Revision of Monocillin VII

Cited by 12 publications

References 73 publications

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

Asymmetric Total Synthesis of (2E)-Macrolactin 3

Structure modification, antialgal, antiplasmodial, and toxic evaluations of a series of new marine-derived 14-membered resorcylic acid lactone derivatives

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