The influence of solvation of the reactions of an allylic carbanion

Atlani, Paul; Biellmann, Jean‐François; Dubé, Serge; Vicens, Jacques

doi:10.1016/s0040-4039(01)92323-8

Cited by 43 publications

(9 citation statements)

References 11 publications

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“…13 Since reaction of A-carbanions of allyl sulfides with carbonyl compounds is known to proceed under kinetic control, 14 the stereochemical outcome can be rationalized through a six-membered cyclic transition state, 14 as shown in Figure 1. The reaction would proceed more preferably through a boat-like transition state, TS-1, than through a chair-form transition state, TS-2, because of the repulsive effect between the electrophile and the substituent (RV) at the 4-position of the bis(oxazoline).…”

Section: Resultsmentioning

confidence: 99%

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

et al. 2003

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The reaction of alpha-lithio allyl aryl sulfides, generated by treatment with n-BuLi and chiral ligands at -78 degrees C, with ketones was examined. The alpha-addition products were formed in preference to the gamma-addition products. The enantioselectivity of the alpha-addition products varied depending on the chiral ligand, and bis(oxazoline)-(t)Bu showed the highest enantioselectivity. Chirality 16:86-89, 2004.

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Section: Resultsmentioning

confidence: 99%

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

et al. 2003

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“…The reaction of the carbanion derived from the y,y-dimethyllallylphenythioether with carbonyl compounds at -20°C in THF in the presence of DABCO occurred at the y center. 6 Indeed the lithium carbanion derived from allylphenylthioether gave with isonicotinaldehyde a mixture in a ratio of 3 to 7 of a reaction product 5 and of reaction products 6 and 7, respectively. The desired alcohol was obtained after chromatography as a mixture of (E) and (Z) isomers 6 and 7 (lll ratio) in a 52% yield.…”

Section: R~r"mentioning

confidence: 99%

Homologous S_NV Reaction: Synthesis of l‐Methyl‐4‐[4′‐phenylsulfonyl‐1′,3′‐butadienyl]pyridinium Iodide and Its Reactivity with Thiol Groups Giving Rise to the Chromophoric Thioether

Holler

Burger

Biellmann

2000

J Chinese Chemical Soc

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Thioether 4‐[(1′E,3′E)‐4′‐phenylsulfanyl‐1,3′‐butadienyl]pyridine 8 and sulfone 4‐(4′‐phenylsulfonyl‐1′,3′‐butadienyl)pyridine 14 were prepared by reaction of the carbanions derived from allylic thioether or allylic sulfone with isonicotinaldehyde. The reaction with the sulfonyl carbanion occurred at the α position and on heating the alcolate gave the dienic sulfone 14. The corresponding pyridinium iodide 10 and 15 were prepared by reaction with methyl iodide, respectively, on pyridine derivates 8 and 14. The dienic pyridinium thioether 10 showed a long wavelength absorption band centered at 420 nm. The reaction of dienic pyridinium sulfone 15 with thiophenol gave the dienic pyridinium thioether 10 by a nucleophilic vinylic substitution. The reaction of sulfone 15 with glutathione was of second order and the rate constant was 8.5 M−1s−1 at 30°C and pH 7, about 500 times smaller than the rate constant observed with (E)‐1‐methyl‐4‐(2‐methylsulfonyl‐1‐ethenyl)pyridinium iodide 1. The dienic pyridinium thioether 10 was a negative solvatochrome.

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“…58 [34] 59 [ b ] [54] 60 [ a ] [55] 61 [ a ] [36,56] [32,33,52,53,83] Propionic ucid-d3-reugents: 0 [58,59] 65 [ a -d ] [60,61] 66 [a,b] 1,l-Bisheterosubstituted allyl anions 45 (Y = e.g. phosphoryl, groups derived therefrom, and also CN, Scheme 6) are more direct, although not always more useful preparative solutions, because an acid, 47, is directly obtained by hydrolysis of the y-adducts 46 (Scheme 5).…”

Section: The Offensive Strategythe Ally1 Anion Route With Many Problemsmentioning

confidence: 99%

The Homoaldol Reaction, or How to Overcome Problems of Regio‐ and Stereo‐selectivity

Hoppe

1984

Angew. Chem. Int. Ed. Engl.

243

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Dedicated to Professor Wolfgang Liittke on the occasion of his 65th birthdayEven today, there are conspicuous gaps in the register of organic synthetic methods. Thus, numerous types of homoenolate reagents are listed; yet no generally applicable method for the homologue of the aldol addition, viz. the homoaldol addition, is to be found. The methods documented up to 1980 offer only singular solutions, and, moreover, are not stereoselective. The present article gives an overview of the existing possibilities and then describes how the gap can be closed by using a new class of homoenolate reagents: 2-alkenyl esters of N,N-diisopropylcarbamic acid are lithiated and the resulting allyllithium compounds tailored to high regio-and diastereoselectivity in addition reactions to the carbonyl group via metal exchange. Altogether, the homoaldol reactions now offer a general and reliable, highly stereoselective entry to y-hydroxycarbonyl compounds, whereby the C(P)-C(y) bond is formed. Furthermore, it is demonstrated how problems associated with the application of ally1 anions as synthetic reagents can be solved today.

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The influence of solvation of the reactions of an allylic carbanion

Cited by 43 publications

References 11 publications

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

Homologous S_NV Reaction: Synthesis of l‐Methyl‐4‐[4′‐phenylsulfonyl‐1′,3′‐butadienyl]pyridinium Iodide and Its Reactivity with Thiol Groups Giving Rise to the Chromophoric Thioether

The Homoaldol Reaction, or How to Overcome Problems of Regio‐ and Stereo‐selectivity

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The influence of solvation of the reactions of an allylic carbanion

Cited by 43 publications

References 11 publications

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

Enantioselective reactions of α‐lithiated allyl aryl sulfides using chiral bis(oxazoline)s

Homologous SNV Reaction: Synthesis of l‐Methyl‐4‐[4′‐phenylsulfonyl‐1′,3′‐butadienyl]pyridinium Iodide and Its Reactivity with Thiol Groups Giving Rise to the Chromophoric Thioether

The Homoaldol Reaction, or How to Overcome Problems of Regio‐ and Stereo‐selectivity

Contact Info

Product

Resources

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Homologous S_NV Reaction: Synthesis of l‐Methyl‐4‐[4′‐phenylsulfonyl‐1′,3′‐butadienyl]pyridinium Iodide and Its Reactivity with Thiol Groups Giving Rise to the Chromophoric Thioether