Synthesis of a C-7 Pd-glycosyl-donor via the base promoted alkylative CO2 trapping with 2-acetylfuran

Francisco, Karol R; Yu, Li; Lindquist-Kleissler, Brent; Xing, Yalan; O’Doherty, George A.

doi:10.1016/j.jcou.2021.101774

Cited by 2 publications

(2 citation statements)

References 31 publications

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“…[14,15] The synthesis began with the base promoted conversion of acetylfuran 8 into βketoester 6. We have explored many different ways to achieve this transformation [16] but have found this is most practically accomplished on scale with the use of NaH as base in the presence of excess dimethylcarbonate. Under these conditions (NaH/CO(OMe) 2 in THF) β-ketoester 6 can be prepared in very good yield (73 %).…”

Section: Resultsmentioning

confidence: 99%

De Novo Asymmetric Approach to Aspergillide‐C: Synthesis of 4‐epi‐seco‐Aspergillide‐C

Xing

O’Doherty

2022

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An asymmetric approach toward the synthesis of the marine natural product aspergillide‐C has been developed. The convergent asymmetric synthesis uses two asymmetric Noyori transfer hydrogenations to enantioselectively prepare the two key fragments, a C‐1 to C‐7 pyranone fragment and a C‐8 to C‐14 β‐keto‐sulfone fragment. The absolute stereochemistry of the pyranone fragment was established by a Noyori reduction of β‐furylketoester to form a furyl alcohol. An Achmatowicz rearrangement was used to stereoselectively convert the furyl alcohol in to the key pyranone fragment. The absolute stereochemistry of the β‐keto‐sulfone fragment was established by a Noyori reduction of an ynone to form a propargyl alcohol. An alkyne zipper isomerization was used to stereospecifically convert the propargyl alcohol in to the β‐keto‐sulfone fragment. Finally, a Pd‐catalyzed C‐glycosylation was used to diastereoselectively couple the two fragments, which when combined with a reduction and Julia‐Kocienski type elimination formed a protected variant of the 4‐epi‐seco‐acid of aspergillide‐C.

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Section: Resultsmentioning

confidence: 99%

De Novo Asymmetric Approach to Aspergillide‐C: Synthesis of 4‐epi‐seco‐Aspergillide‐C

Xing

O’Doherty

2022

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“… , The synthesis began with the base-promoted Claisen condensation of acetylfuran 14 to form β-ketoester 17 . While we have explored many different ways to achieve this transformation, this was most practically accomplished on scale with the use of NaH as a base in the presence of excess dimethyl carbonate. Under these conditions (NaH/CO(OMe) 2 in THF), β-ketoester 17 can be prepared in a very good yield (73%).…”

Section: Resultsmentioning

confidence: 99%

Synthetic Efforts and Ultimate Limitation to an Asymmetric Achmatowicz Approach Toward EBC-23

Wang

O’Doherty

2022

J. Org. Chem.

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An effort toward the total synthesis of the polyketide natural product EBC-23 is reported. The asymmetric approach is convergent and uses a late-stage Claisen-like enolate/acid chloride coupling to establish a key 1,3-diketone intermediate. The 1,3-diketone target is an oxidized form of the hydrated natural product, which fails to spiroketalize. The convergent asymmetric synthesis uses an asymmetric Noyori transfer hydrogenation of a β-furyl ketoester to enantioselectively form a chiral furyl alcohol. An Achmatowicz/Jones/Luche three-step reaction sequence was used to stereoselectively convert the furyl alcohol into the 5-hydroxy-pyran-2-one. The absolute stereochemistry of the 1,3-polyol fragment was established by a Leighton allylation. A subsequent Grubbs cross-metathesis, and Evans acetalation were used to install the 1,3-syn-diol stereochemistry.

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Synthesis of a C-7 Pd-glycosyl-donor via the base promoted alkylative CO2 trapping with 2-acetylfuran

Cited by 2 publications

References 31 publications

De Novo Asymmetric Approach to Aspergillide‐C: Synthesis of 4‐epi‐seco‐Aspergillide‐C

De Novo Asymmetric Approach to Aspergillide‐C: Synthesis of 4‐epi‐seco‐Aspergillide‐C

Synthetic Efforts and Ultimate Limitation to an Asymmetric Achmatowicz Approach Toward EBC-23

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