Substitution nucleophile d'acetates de cyclenols allyliques fonctionnels par des organometalliques en presence de sels cuivreux. Application a une synthese rapide de la (±)mitsugashiw alactone

Amri, Hassen; Rambaud, M.; Villiéras, J.

doi:10.1016/s0040-4020(01)81522-2

Cited by 52 publications

(15 citation statements)

References 13 publications

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“…It must be noted that Amri et al. have attempted unsuccessfully to isolate similar putative enolates as silyl ketene acetals, a failure that could be due to rapid elimination during quenching 24…”

Section: Resultsmentioning

confidence: 99%

“…It must be noted that Amri et al have attempted unsuccessfully to isolate similar putative enolates as silyl ketene acetals, a failure that could be due to rapid elimination during quenching. [24] The MBHA used for this experiment was designed so as to accelerate the desired Ireland-Claisen rearrangement as much as possible and at the same time to limit the probability of direct or indirect allylic substitution. For this purpose, MBHA 6 m was synthesized, as shown in Scheme 5.…”

Section: Investigation Of a P-michael Addition/elimination Pathwaymentioning

confidence: 99%

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Probing the Mechanism of Allylic Substitution of Morita–Baylis–Hillman Acetates (MBHAs) by using the Silyl Phosphonite Paradigm: Scope and Applications of a Versatile Transformation

Kalyva

Zografos

Kapourani

et al. 2015

Chemistry A European J

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A P-C bond-forming reaction between silyl phosphonites and Morita-Baylis-Hillman acetates (MBHAs) is explored as a general alternative towards medicinally relevant β-carboxyphosphinic structural motifs. Conversion rates of diversely substituted MBHAs to phosphinic acids 9 or 14 that were recorded by using (31) P NMR spectroscopy revealed unexpected reactivity differences between ester and nitrile derivatives. These kinetic profiles and DFT calculations support a mechanistic scenario in which observed differences can be explained from the "lateness" of transition states. In addition, we provide experimental evidence suggesting that enolates due to initial P-Michael addition are not formed. Based on the proposed mechanistic scenario in conjunction with DFT calculations, an interpretation of the E/Z stereoselectivity differences between ester and nitriles is proposed. Synthetic opportunities stemming from this transformation are presented, which deal with the preparation of several synthetically capricious phosphinic building blocks, whose access through the classical P-Michael synthetic route is not straightforward.

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Section: Resultsmentioning

confidence: 99%

Section: Investigation Of a P-michael Addition/elimination Pathwaymentioning

confidence: 99%

Probing the Mechanism of Allylic Substitution of Morita–Baylis–Hillman Acetates (MBHAs) by using the Silyl Phosphonite Paradigm: Scope and Applications of a Versatile Transformation

Kalyva

Zografos

Kapourani

et al. 2015

Chemistry A European J

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“…As in the first‐generation synthesis, aryl ether 6 6 was prepared in good yield (72 %) and with high enantiomeric excess (87 % to 88 % ee ) by palladium‐catalyzed reaction of 2‐bromovanillin ( 7 )17 with carbonate 8 (available in two steps from glutaraldehyde and the Emmons–Wadsworth–Horner reagent)18 in the presence of chiral ligand 9 (Scheme ). All attempts to effect the intramolecular Heck reaction of aryl ether 6 failed in our previous synthesis, resulting primarily in ionized product phenol 7 .…”

Section: Methodsmentioning

confidence: 99%

An Efficient Enantioselective Synthesis of (−)-Galanthamine

Trost

Tang

2002

Angew. Chem.

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Aller guten Reaktionen sind drei: Palladium‐katalysierte asymmetrische Allylierung, Heck‐Cyclisierung und diastereoselektive Oxidation in Allylstellung kamen bei der Totalsynthese von (−)‐Galanthamin 3 zum Einsatz, das ausgehend von 1 und 2 (Troc=2,2,2‐Trichlorethoxycarbonyl) in 14.8 % Gesamtausbeute und mit 96 % ee erhalten wurde. Diese Synthese ist die kürzeste und effizienteste nichtbiomimetische Route zum Acetylcholinesterase‐Hemmer 3.

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“…28 (-)-Codeine was obtained in 15 steps from guaiacol derivative 21 in an overall yield of 7%. It should be mentioned that compound 24 also served as an intermediate for total synthesis of (-)-galanthamine (29) as shown in Scheme 6. Scheme 6 Reagents and conditions: (a) SeO 2 , Na 2 HPO 4 , 1,4-dioxane (64%); (b) MeNH 2 , MeOH; (c) DIBALH (4 equiv), then aq NaH 2 PO 4 ; (d) NaCNBH 3 (b-d in one pot, 62%).…”

Section: Trostmentioning

confidence: 99%