Total Syntheses of Natural Tubelactomicins B, D, and E:  Establishment of Their Stereochemistries

Sawamura, Kiyoto; Yoshida, Kôji; Suzuki, Akari; Motozaki, Toru; Kozawa, Ikuko; Hayamizu, Takashi; Munakata, Ryosuke; Takao, Ken Ichi; Tadano, Kin Ichi

doi:10.1021/jo0708442

Cited by 23 publications

(12 citation statements)

References 13 publications

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“…Methyl 2-(hydroxymethyl)acrylate (23) [22] was converted into the E-vinylbromide 24 through a sequence of O-MOM protection, bromination, and stereoseletive b elimination of HBr. [23] A Liebeskind-modified Stille coupling between 24 and tributylvinylstannane in the presence of copper thiophene carboxylate (CuTC) provided the diene 25 in 75 % yield. [24] We noted that the Suzuki-Miyaura crosscoupling between 24 and either vinyl potassium trifluoroborate, vinylpinacolborane, or vinyl boroxine afforded the desired diene 25 in a low yield (20 to 40 %).…”

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confidence: 99%

Enantioselective Synthesis of Putative Lipiarmycin Aglycon Related to Fidaxomicin/Tiacumicin B

et al. 2014

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An enantioselective synthesis of a putative lipiarmycin aglycon was accomplished and features: 1) Brown's enantioselective alkoxyallylboration and allylation of aldehydes, 2) chain elongation by iterative Horner-Wadsworth-Emmons olefination, 3) Evans' aldol reaction and 4) an ene-diene ring-closing metathesis. A neighboring-group-assisted chemoselective reductive desilylation was uncovered in this study and was instrumental to the realization of the present synthesis.

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confidence: 99%

Enantioselective Synthesis of Putative Lipiarmycin Aglycon Related to Fidaxomicin/Tiacumicin B

et al. 2014

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“…Deprotection of poly(2‐MOM) Acid‐catalyzed hydrolysis of MOM group for poly(2‐MOM) was carried out according to the literature . Poly(2‐MOM) was treated with conc .…”

Section: Resultsmentioning

confidence: 99%

“…1‐MOM : Yield 60.6%; Purity 100%; bp 32.5 °C/ 0.20 mmHg; d = 1.06 g/mL; 1 H NMR (400 MHz, 30 °C, CDCl 3 ): δ 6.32 (s, 1H, CH 2 =), 5.89 (s, 1H, CH 2 =), 4.68 (s, 2H, −OCH 2 O−), 4.29 (s, 2H, C=CCH 2 O−), 3.78 (s, 3H, −OCH 3 ), 3.39 (s, 3H, −CH 3 ) ppm; 13 C NMR (100 MHz, CDCl 3 , 298 K) δ 166.2, 167.0, 126.2, 96.0, 65.7, 55.3, 51.8 ppm.…”

Section: Experimental Partmentioning

confidence: 99%

Stereospecific Anionic Polymerization of α‐(Hydroxymethyl)acrylate with Protective Group

Kohsaka

Suzawa

Kitayama

2015

Macromolecular Symposia

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Summary: Anionic polymerizations of hydroxyl-protected α-(hydroxymethyl) acrylates were investigated. The methyl ester with methoxymethyl (1-MOM) and allyl (1-allyl) protecting groups were polymerized by isopropyl α-lithioisobutyrate (Li-iPrIB) in toluene at 78 °C, affording highly isotactic polymers. Similarly, the polymerization of ethyl ester (2-MOM) gave an isotactic polymer, while those of t-butyl (3-MOM) and isobutyl (4-MOM) ester did not form any polymeric products. The hydrolysis of poly(2-MOM) in acidic conditions resulted in the deprotection of MOM group, although the acid also catalyzed the ester exchange between the neighboring units to form lactone units, as observed by 1 H NMR analysis, IR spectroscopy and thermogravimetric analysis. A film of poly(2-MOM) exposed to HCl vapor for 2 h became insoluble in any organic solvents due to the lactonization in solid state.

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“…[6] In 2005, we reported the total synthesis of 1, thereby confirming the stereochemistry of the (+) natural form. [9] As a result, we established the unknown relative and absolute stereochemistries of 2-4 as those depicted in Figure 1. [8] Later, we accomplished the total syntheses of tubelactomicins 2-4 by synthetic approaches slightly modified from that used for the total synthesis of 1.…”

Section: Total Synthesis Of (+)-Tubelactomicinsmentioning

confidence: 99%

Natural Product Synthesis Featuring Intramolecular Diels–Alder Approaches – Total Syntheses of Tubelactomicins and Spiculoic Acid A

Tadano

2009

Eur J Org Chem

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We have recently accomplished the total syntheses of the antimicrobial tricyclic 16‐membered macrolides (+)‐tubelactomicin A, B, D, and E by common synthetic approaches based on intramolecular Diels–Alder (IMDA) reactions. These total syntheses established the relative and absolute configurations of three antibiotics – (+)‐tubelactomicins B, D, and E – for which only planar structures had been previously reported. In addition, we have very recently accomplished the total synthesis of a marine natural product, (+)‐spiculoic acid A, by an IMDA strategy. This Microreview summarizes our total syntheses of the four tubelactomicns and the total synthesis of (+)‐tubelactomicin A by Tatsuta et al. Both approaches were based on the use of stereoselective IMDA reactions for the construction of the lower‐half segments of the antibiotics. Total syntheses of the unnatural (–) and natural (+) enantiomers of spiculoic acid A, the former achieved by Baldwin and Lee's group and the latter achieved by the author's group, are also summarized. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Total Syntheses of Natural Tubelactomicins B, D, and E: Establishment of Their Stereochemistries

Cited by 23 publications

References 13 publications

Enantioselective Synthesis of Putative Lipiarmycin Aglycon Related to Fidaxomicin/Tiacumicin B

Enantioselective Synthesis of Putative Lipiarmycin Aglycon Related to Fidaxomicin/Tiacumicin B

Stereospecific Anionic Polymerization of α‐(Hydroxymethyl)acrylate with Protective Group

Natural Product Synthesis Featuring Intramolecular Diels–Alder Approaches – Total Syntheses of Tubelactomicins and Spiculoic Acid A

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