Stereo- and regiochemistry of a palladium-catalyzed oxygen to carbon migration

Trost, Barry M.; Runge, Thomas A.

doi:10.1021/ja00399a090

Cited by 26 publications

(5 citation statements)

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“…Unfortunately, all attempts to reduce the corresponding aminonaphthoquinone 55 met with failure . We therefore explored an amination protocol developed by Trost using azidomethylphenyl sulfide as a synthon for electrophilic NH 2 + . , Accordingly, treatment of the Grignard derived from bromonaphthalene 57 with azidomethylphenyl sulfide followed by a basic hydrolytic workup to decompose triazene intermediate 59 provided unstable (air-sensitive) amine 56 in low yield (∼24%), with the remainder of the mass balance being reduced naphthalene 60 (62%). Quenching lithium intermediate 58a with aqueous ammonium chloride yielded 60 in 72% yield.…”

Section: Resultsmentioning

confidence: 99%

Rifamycin Biosynthetic Congeners: Isolation and Total Synthesis of Rifsaliniketal and Total Synthesis of Salinisporamycin and Saliniketals A and B

Feng

Carrasco

et al. 2016

J. Am. Chem. Soc.

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We describe the isolation, structure elucidation, and total synthesis of the novel marine natural product rifsaliniketal and the total synthesis of the structurally related variants salinisporamycin and saliniketals A and B. Rifsaliniketal was previously proposed, but not observed, as a diverted metabolite from a biosynthetic precursor to rifamycin S. Decarboxylation of rifamycin provides salinisporamycin, which upon truncation with loss of the naphthoquinone ring leads to saliniketals. Our synthetic strategy hinged upon a Pt(II)-catalyzed cycloisomerization of an alkynediol to set the dioxabicyclo[3.2.1]octane ring system and a fragmentation of an intermediate dihydropyranone to forge a stereochemically defined (E,Z)-dienamide unit. Multiple routes were explored to assemble fragments with high stereocontrol, an exercise that provided additional insights into acyclic stereocontrol during stereochemically complex fragment-assembly processes. The resulting 11-14 step synthesis of saliniketals then enabled us to explore strategies for the synthesis and coupling of highly substituted naphthoquinones or the corresponding naphthalene fragments. Whereas direct coupling with naphthoquinone fragments proved unsuccessful, both amidation and C-N bond formation tactics with the more electron-rich naphthalene congeners provided an efficient means to complete the first total synthesis of rifsaliniketal and salinisporamycin.

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Section: Resultsmentioning

confidence: 99%

Rifamycin Biosynthetic Congeners: Isolation and Total Synthesis of Rifsaliniketal and Total Synthesis of Salinisporamycin and Saliniketals A and B

Feng

Carrasco

et al. 2016

J. Am. Chem. Soc.

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“…34 It was later found that a complementary Pdligand combination would provide the cycloheptanone product (eqn 17). 35 Formation of cyclopentanone 48 presumably proceeds by coordination of Pd(0) to the 1,1-disubstituted olefin of 46 followed by an S N 2 attack to create the zwitterionic intermediate 47, Scheme 8 which subsequently collapses in regioselective fashion. 36 The reaction proceeds with overall retention of configuration by double inversion (Scheme 9).…”

Section: Transition Metal(0)-mediated Reactionsmentioning

confidence: 99%

“…In this case ion pairing does not explain their results, which remain consistent with their insideattack model. 68 (35) (36) (37)…”

Section: Scheme 15mentioning

confidence: 99%

The [1, 3] O-to-C rearrangement: opportunities for stereoselective synthesis

Nasveschuk

Rovis

2008

Org. Biomol. Chem.

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The relay of stereochemistry of a breaking C-O bond into a forming C-C bond is well-known in the context of [3, 3] sigmatropic shifts; however, this useful strategy is less well-known in other types of molecular rearrangements. Though the first successful example of a [1, 3] O-to-C rearrangement was reported more than 100 years ago, this class of reactions has received less attention than its [3, 3] counterpart. This perspective analyzes the various methods used for the activation and [1, 3] rearrangement of vinyl ethers with an emphasis on mechanism and applications to stereoselective synthesis. We also highlight our own contributions to this area.

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“…In pathways B and C, the final cyclization could be classified as 4‐ enolendo‐exo‐trig , which would be disfavored according to Baldwin's rules . However formally‐disfavored enolendo ‐cyclizations have been proposed when zwitterionic intermediates are involved, and therefore cannot be completely ruled out as a possibility in this case.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Fused Indoline‐Cyclobutanone Derivatives via an Intramolecular [2+2] Cycloaddition

et al. 2019

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A serendipitously‐discovered process for the synthesis of heterocyclic products containing a novel fused indoline‐cyclobutanone ring system is reported. This process is believed to take place through in situ generation of a ketene intermediate, followed by intramolecular [2+2] cycloaddition with a pendant enamide. The formation of a ketene intermediate in this process is significant as the reaction conditions employed are analogous to those commonly used in tertiary amine Lewis base catalysis, where the potential intermediacy of ketenes is an important consideration that is often overlooked.

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Stereo- and regiochemistry of a palladium-catalyzed oxygen to carbon migration

Cited by 26 publications

References 0 publications

Rifamycin Biosynthetic Congeners: Isolation and Total Synthesis of Rifsaliniketal and Total Synthesis of Salinisporamycin and Saliniketals A and B

Rifamycin Biosynthetic Congeners: Isolation and Total Synthesis of Rifsaliniketal and Total Synthesis of Salinisporamycin and Saliniketals A and B

The [1, 3] O-to-C rearrangement: opportunities for stereoselective synthesis

Synthesis of Fused Indoline‐Cyclobutanone Derivatives via an Intramolecular [2+2] Cycloaddition

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