Concept

Réactif de Grignard

Publications associées (148)

A highly stereoselective synthesis of (2S, 3S)-beta -hydroxyleucine

An efficient asym. synthesis of (2S,3S)-beta -hydroxyleucine is described. The key step in the synthesis was a highly diastereoselective nucleophilic addn. of Grignard reagent to N,N-dibenzyl-O-TBS-serinal (TBS = SiMe2CMe3). This strategy should be applica ...

1997

Ab Initio Molecular Dynamics Investigation of Singlet C2H2Li2: Determination of the Ground State Structure and Observation of LiH Intermediates

The structural, electronic, and dynamic properties of the organolithium compd. C2H2Li2 were studied via ab initio mol. dynamics simulations based on the Car-Parrinello method. Dynamic simulated annealing techniques applied to search for the low-energy conf ...

1995

Synthesis of Polypropionate Fragments Containing Tertiary-Alcohol Moieties - Cross-Aldolisations with Lithium Enolates of 7-Oxabicyclo[2.2.1]Heptan-2-One Derivatives

Pierre Vogel

The Diels-Alder adduct of 2,4-dimethylfuran to 1-cyanovinyl (1'R)-camphanate ((+)-(1R,2S,4R)-2-exo-cyano-1,5-dimethyl-7-oxabicyclo[2.2.1]hept-5-en-2- endo-yl (1'R)-camphanate ((+)-1)) was converted into (+)-2,7-dideoxy-2,4-di-C-methyl-L-glycero-((+)-6) and ...

1995

DEALLYLATION REAGENT AND DEALLYLATION METHOD USING SAID REAGENT

Reagent and method useful for splitting a protected function, in the event of organic synthesis by an allyl group with the latter. The reagent is characterized by having a) a solvent system; b) a catalyst comprising at least one element from column VIII of ...

1994

Asymmetric synthesis. 29. Preparation of 1,8-diazaspiro[5.5]undecane derivatives

Jieping Zhu

From 2-cyano-6-phenyloxazolopiperidine, two highly efficient routes have been developed for the asym. synthesis of the spiropiperidine system: 1,8-diazaspiro[5.5]undecane. The key step was generation of the imine salts from the functionalized alpha -amino ...

1993

An efficient procedure for the regioselective monoprotection of 1,2-diols

Jieping Zhu

Regioselective nucleophilic ring opening of isopropylidene ketals of simple diols or sugars, e.g. I (R = Ac, CH2Ph), by AlMe3 gave the corresponding II (R = H, CH2PH). This reagent offers a new method for selective monoprotection of 1,2-diols. [on SciFinde ...

1992

The two-fold reaction benchmark applied to the copper catalyzed assembling of 1,w-difunctional hydrocarbon chains

Long-chain hydrocarbons carrying vinyl groups, chlorine atoms or oxygen functions at the terminal positions can be prepd. with excellent yields by copper mediated coupling of alkyl tosylates and Grignard reagents. E.g., Li2CuCl4 catalyzed the coupling of C ...

1991

gem-Difluorocyclopropanes: an improved method for their preparation

By treatment with Br2CF2 and Ph3P, 4 unfunctionalized olefins, 4 enol ethers and 1 bis-enol ether were converted to gem-difluorocyclopropanes. Thus, RCH:CHOPr (R = H, Me) gave difluorocyclopanes I in 73 and 83% yield, resp. The yields were considerably inc ...

1990

Superbases for organic synthesis

A review with 70 refs. LICKOR mixts. of organolithium reagents and bulky potassium alcoholates allow the smooth metalation and subsequent electrophilic substitution of low acidity hydrocarbons, in particular olefins. The allylpotassium intermediates exhibi ...

1988

o-Selective metalation and electrophilic substitution of benzylamine derivatives

N-Pivaloylbenzylamines and derivs. [e.g., 2,4-R(MeO)C6H4CH2NHCOCMe3, I, R = H] undergo smooth ortho-metalation when treated with two equivs. of an organolithium reagent. Subsequent carboxylation or hydroxylation lead to a no. of products, e.g., I, R = CO2H ...

1988

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