Synthesis of (.+-.)-Fredericamycin A

Wendt, John A.; Gauvreau, P. J.; Bach, Robert D.

doi:10.1021/ja00101a013

Cited by 66 publications

(30 citation statements)

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“…Consequently, a model ABCD-ring system was first investigated to test the viability of this proposed reaction. Kraus annulation 9 of cyanophthalide 17 10 with ent -AB-/HG-enone ent- 9 8 under rigorously oxygen-free conditions gave ABCD-tetracycle (−)- 18 (Scheme 4). Deoxygenation was critical for the success of the annulation, as adventitious oxygen caused decomposition.…”

Section: Resultsmentioning

confidence: 99%

Total Syntheses of HMP-Y1, Hibarimicinone, and HMP-P1

2012

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Total syntheses of HMP-Y1, atrop-HMP-Y1, hibarimicinone, atrop-hibarimicinone, and HMP-P1 are described using a two-directional synthesis strategy. A novel benzyl fluoride Michael–Claisen reaction sequence was developed to construct the complete carbon skeleton of HMP-Y1 and atrop-HMP-Y1 via a symmetrical, two-directional, double annulation. Through efforts to convert HMP-Y1 derivatives to hibarimicinone and HMP-P1, a biomimetic mono-oxidation to desymmetrize protected HMP-Y1 was realized. A two-directional unsymmetrical double annulation and biomimetic etherification were developed to construct the polycyclic and highly-oxidized skeleton of hibarimicinone, atrop-hibarimicinone, and HMP-P1. The use of a racemic biaryl precursor allowed for the synthesis of both hibarimicinone atropisomers and provides the first confirmation of the structure of atrop-hibarimicinone. Additionally, this work documents the first reported full characterization of atrop-hibarimicinone, HMP-Y1, atrop-HMP-Y1, and HMP-P1. Lastly, a pH-dependent rotational barrier about the C2–C2' bond of hibarimicinone was discovered, which provides valuable information necessary to achieve syntheses of the glycosylated congeners of hibarimicinone.

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Section: Resultsmentioning

confidence: 99%

Total Syntheses of HMP-Y1, Hibarimicinone, and HMP-P1

2012

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“…A new, linear synthesis of the highly oxygen-substituted polyaromatic, fredericamycin A (1) was elucidated by the combination of the oxidative intramolecular [4 2] cycloaddition of the suitably functionalized (phenylthio)acetylene ± Co 2 (CO) 6 complex 25 and the aromatic Pummerer-type reaction of the sulfoxide 26 with 1-ethoxyvinyl chloroacetate (7 b). Application of this protocol to the optically pure intermediate 10 would lead to the total synthesis of natural 1 and its derivatives and is now in progress in our laboratory.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of the Antitumor Antibiotic (±)-Fredericamycin A by a Linear Approach

et al. 2000

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A linear approach to the total synthesis of racemic fredericamycin A (1) through the oxidative intramolecular [4 + 2] cycloaddition of a (phenylthio)acetylene-cobalt complex is described, which is applicable for the asymmetric total synthesis of naturally occuring 1. The highlight of this work is the aromatic Pummerer-type reaction with 1-ethoxyvinyl chloroacetate, which effects the introduction of the oxygen functional group to the internal B-ring of the highly functionalized, congested polyaromatic ABC-ring moiety.

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“…29 The semipinacol rearrangements of 2-hydroxy selenolates are very similar to those of 2-hydroxy thiolates, but most of the rearrangements occur only if the selenyl moiety is attached to a fully substituted carbon. Till now, the rearrangement has been applied mainly to the ring expansion of cyclic ketones.…”

Section: Thiolates or Selenolates As Leaving Groupmentioning

confidence: 99%