A Nozaki−Hiyama−Kishi Ni(II)/Cr(II) Coupling Approach to the Phomactins

Mi, Baoyu; Maleczka, Robert E.

doi:10.1021/ol015807q

Cited by 57 publications

(9 citation statements)

References 36 publications

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“…13, 25 Lastly, Maleczka and Mi have synthesised analogues of the platelet activating factor (PAF) antagonists phomactins A, C and D from a trisubstituted alkene (227) prepared with the modified Julia olefination. 107 The sodium metallate of BT-sulfone 225 was treated with aldehyde 226 in DME solvent **** Dienal 232 exists in dynamic equilibrium with a 2H-pyran tautomer resulting from 6π-electron electrocyclisation. and gave a 66% yield of 227 following acetal hydrolysis.…”

Section: Synthesis Of Trisubstituted Alkene Targetsmentioning

confidence: 99%

The modified Julia olefination: alkene synthesis via the condensation of metallated heteroarylalkylsulfones with carbonyl compounds

Blakemore

2002

J. Chem. Soc., Perkin Trans. 1

640

313

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Section: Synthesis Of Trisubstituted Alkene Targetsmentioning

confidence: 99%

The modified Julia olefination: alkene synthesis via the condensation of metallated heteroarylalkylsulfones with carbonyl compounds

Blakemore

2002

J. Chem. Soc., Perkin Trans. 1

640

313

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“…The newly produced secondary alcohol group in 16a was assigned the β-stereochemistry from NOE studies, and was confirmed by carrying out an X-ray crystal structure determination on the corresponding p-nitrobenzoate (PNB) derivative 16b. In later related studies, 12 Mi and Maleczka showed that the substrate 17 underwent a Cr()-Ni() macrocyclisation leading to the secondary alcohol product 18 with exclusively the α-stereochemistry shown. The β-stereochemistry of the secondary alcohol in 16a, presumably results from cyclisation of the aldehyde vinyl iodide 14 via the s-trans conformation, as shown.…”

Section: Resultsmentioning

confidence: 98%

A total synthesis of (±)-phomactin A

2003

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A total synthesis of the PAF antagonist phomactin A (1), isolated from the marine fungus Phoma sp. is described. The synthesis is based on a Cr(II)/Ni(II) macrocyclisation from the aldehyde vinyl iodide 14, leading to the key phomactatrienol intermediate 16a, followed by elaboration of 16a to the epoxyketone 21, which undergoes spontaneous pyran and hemiacetal ring formation to 1 on deprotection with DDQ.

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“…Pattenden's synthetic strategy, 51 similarly evoked by Maleczka, 161 involved the treatment of vinyl iodide 146 with chromium(II) and nickel(II) chlorides, to afford the allylic alcohol 147 in moderate yield (Scheme 30a). Following inversion of the secondary alcohol and diastereoselective monoepoxidation, 22 was obtained after ultimate double deprotection concomitant with acetal formation and epoxide opening.…”

Section: Addition To Carbonylsmentioning

confidence: 99%

Unconventional Macrocyclizations in Natural Product Synthesis

2020

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Over the past several decades, macrocyclic compounds have emerged as increasingly significant therapeutic candidates in drug discovery. Their pharmacological activity hinges on their rotationally restricted three-dimensional orientation, resulting in a unique conformational preorganization and a high enthalpic gain as a consequence of high-affinity macrocycle–protein binding interactions. Synthetic access to macrocyclic drug candidates is therefore crucial. From a synthetic point of view, the efficiency of macrocyclization events commonly suffers from entropic penalties as well as undesired intermolecular couplings (oligomerization). Although over the past several decades ring-closing metathesis, macrolactonization, or macrolactamization have become strategies of choice, the toolbox of organic synthesis provides a great number of versatile transformations beyond the aforementioned. This Outlook focuses on a selection of examples employing what we term unconventional macrocyclizations toward the synthesis of natural products or analogues.

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A Nozaki−Hiyama−Kishi Ni(II)/Cr(II) Coupling Approach to the Phomactins

Cited by 57 publications

References 36 publications

The modified Julia olefination: alkene synthesis via the condensation of metallated heteroarylalkylsulfones with carbonyl compounds

The modified Julia olefination: alkene synthesis via the condensation of metallated heteroarylalkylsulfones with carbonyl compounds

A total synthesis of (±)-phomactin A

Unconventional Macrocyclizations in Natural Product Synthesis

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