The Oxazolomycins: A Structurally Novel Class of Bioactive Compounds

Moloney, Mark G.; Trippier, Paul C.; Yaqoob, Muhammad; Wang, Zhaoyang

doi:10.2174/1570163043334974

Cited by 57 publications

(45 citation statements)

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“…Since the isolation of (+)‐neooxazolomycin ( 1 ; Scheme ) in 1985, a number of members of this family have been identified, including oxazolomycins A–C, oxazolomycin A2, bisoxazolomycin A, 16‐methyloxazolomycin, curromycins A and B, KSM‐2690 B–C, and lajollamycins A–D . These oxazolomycins exhibit a wide range of potent antibacterial and antiviral activities as well as in vivo antitumor activity . Because of their structural complexity and potent biological activities, considerable attention has been paid to their synthesis .…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Total Synthesis of (+)‐Neooxazolomycin Using a Chirality‐Transfer Strategy

Kim

Song

et al. 2019

Angewandte Chemie

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The total synthesis of (+ +)-neooxazolomycin was achieved from the amino-acid d-serine.T he efficiency of this approach is derived from the use of principles of memory of chirality and dynamic kinetic resolution in the intramolecular aldol reaction of as erine derivative to build the densely functionalizedl actam framework and to install three contiguous stereocenters.T he key intermediate was readily elaborated to the target natural product.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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Section: Methodsmentioning

confidence: 99%

Asymmetric Total Synthesis of (+)‐Neooxazolomycin Using a Chirality‐Transfer Strategy

Kim

Song

et al. 2019

Angewandte Chemie

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“…1 Of significance is the fact that the bicyclic motif common to these natural products occurs more widely, for example, in the cinnabarimides 2 and the oxazolomycins. 3 Our interest in methodology providing access to enantiopure tetramate systems has led to the development of a sequence based upon Dieckmann or aldol ring closure, 4-7 critical to the success of which has been the application of Seebach's Self Regeneration of Stereocentres concept. 8 We report here that further elaboration of these systems by reaction of the tetramate C-6 carbonyl group with dithiane anions, chosen for their potential for further elaboration to analogues of lactacystin and oxazolomycin, is possible in a reaction which is controlled by the inherent steric and stereoelectronic bias of the bicyclic structure, but that an unexpected rearrangement capable of compromising the stereochemical or the skeletal integrity of the product can occur.…”

Section: Introductionmentioning

confidence: 99%

Equilibration in bicyclic pyroglutamates by ring opening-reclosure

Moloney

Yaqoob

2008

Tetrahedron Letters

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“…These oxazolomycins were found to exhibit wide‐ranging and potent antibacterial and antiviral activities as well as in vivo antitumor activity. Their intriguing molecular architectures and biological activities make these compounds attractive targets for synthesis 2. 3 In 1990, Kende et al.…”

Section: Methodsmentioning

confidence: 99%

Total Synthesis of Neooxazolomycin

et al. 2007

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Dedicated to Professor Yoshito Kishi on the occasion of his 70th birthdayNeooxazolomycin and oxazolomycin A, originally isolated from a strain of Streptomyces by Uemura and co-workers in 1985, [1] together with the seven other congeners identified to date constitute a family of structurally unique oxazole polyene lactam-lactone antibiotics. These oxazolomycins were found to exhibit wide-ranging and potent antibacterial and antiviral activities as well as in vivo antitumor activity. Their intriguing molecular architectures and biological activities make these compounds attractive targets for synthesis. [2,3] In 1990, Kende et al. disclosed the synthesis of neooxazolomycin, [4] and this superb achievement is the first and only total synthesis of any member of this family; however the stereocontrolled construction of the right-hand core has remained an unanswered challenge.Our synthetic plan for neooxazolomycin makes a disconnection at the amide linkage to give the left-hand segment 1 and right-hand segment 2 (Scheme 1). Since Kende et al. had already demonstrated an effective method for the synthesis of 1 [4] by a Reformatsky-type aldol reaction [5] and Stille coupling, [6] the major challenge in the synthesis resided in the stereoselective construction of 2. From the retrosynthetic perspective, we envisioned pyrrolidinone 4 as a precursor of 2 with considerably less structural complexity which would lead to 2 through a Nozaki-Hiyama-Kishi reaction [7] and stereoselective dihydroxylation with concomitant lactonization. We postulated that this precursor could be accessed by a palladium-catalyzed cyclization of amide 5. This approach is particularly appealing since the three contiguous stereogenic centers including two quaternary centers could be created by one dihydroxylation process. The required amide 5 was synthesized in a completely stereoselective manner by taking advantage of the intramolecular hydrosilylation [8] developed by Tamao et al. [9] (Scheme 2). Thus, alkynol 8 was first prepared by the coupling of alkyne 6 [10] and triflate 7, [11] both readily available from (S)hydroxy-2-methylpropanoate, followed by desilylation. Reaction of 8 with tetramethyldisilazane provided hydrodimethylsilyl ether 9, which upon hydrosilylation with [Pt(dvds)] [12] as a catalyst in THF at room temperature followed by exposure of the resulting siloxane 10 to iodine in the presence of CsF in Scheme 1. Retrosynthetic analysis of neooxazolomycin. Bn = benzyl, Fmoc = 9-fluorenylmethyloxycarbonyl.

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The Oxazolomycins: A Structurally Novel Class of Bioactive Compounds

Cited by 57 publications

References 0 publications

Asymmetric Total Synthesis of (+)‐Neooxazolomycin Using a Chirality‐Transfer Strategy

Asymmetric Total Synthesis of (+)‐Neooxazolomycin Using a Chirality‐Transfer Strategy

Equilibration in bicyclic pyroglutamates by ring opening-reclosure

Total Synthesis of Neooxazolomycin

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