Georges Roussi

Action des organomagnesiens sur les alcools allyliques en presence de complexes du nickel: I. Synthese d'olefines

Abstract The reaction between Grignard reagents, RMgX (R  Me, Ph, PhCH 2 ), and allylic alcohols R′CHCHC(OH)(H)R′′, in the presence of catalytic amounts of (Ph 3P ) 2 NiCl 2 , leads to a mixture of olefins (R′CHCHC(R)(H)R′′ + R′C(R)(H)CHCHR′′). This reaction constitutes a route to compounds with a quaternary carbon atom attached to germinal vinyl and methyl groups; thus, 1-vinylcyclohexanol and MeMgBr afford 1-methyl-1-vinylcyclohexane as the major product. The catalytic cycle probably involves π-allyl complexes of nickel, and intermediates with NiMg bonds.

Substitution nucléophile aromatique radicalaire. Nouvelle synthèse du squelette indole

Abstract A new method is described, based on the S RN 1 reaction, which takes advantage of the regiospecific formation of an ortho -NH 2 -functionalized aryl radical. In the presence of three different series of nucleophiles, (aliphatic ketone enolates, aldehyde enolates, cyclic and heterocyclic ketone enolates), some used for the first time in an S RN 1 reaction, the indole skeleton is obtained in one step in yields ranging from 20 to 85 % Ketone enolates give 2-substituted indoles while aldehyde enolates give 3-substituted indoles; cyclic enolates tricyclic indoles ( 29 and 30 ). This versatile indohzation method (using non-acidic conditions) is thus of synthetic utility and considerably enlarges the scope of the S RN ,1 reaction.

Studies on SRN1 reactions-9 : A new access to the isoquinoline ring system☆

Abstract The SRN1 reaction between o-halogeno-benzylamines and enolates derived from a series of ketones and aldehydes affords 1, 2 dihydro-isoquinolines from which are obtained (i)the isoquinoline derivatives, either spontaneously or by treatment on Pd-C and (ii) the 1,2,3,4 tetrahydro-isoquinoline derivatives after sodium borohydride reduction.

Synthesis of a model of chloropeptins I, II western subunit by the intramolecular SNAr based methodology

Abstract Formation of a biaryl ether bond between the termini of a tetrapeptide containing a highly racemization prone amino acid by the intramolecular SNAr reaction afforded two diastereomeric 16-membered macrocycles along with their respective atropoisomers. The (R,S,R) and its atropoisomer constituted a model of chloropeptins I, II western part.

The first synthesis of simplified 16- and 17-membered ring macropolypeptides containing the phenyl-indole system of kistamycin and chloropeptin I, II

Abstract The synthesis of simplified 16- and 17-membered ring macropolypeptides was achieved by Ni 0 mediated carbon-carbon ring closure of properly substituted linear precursors.

Indole arylation studies directed towards the synthesis of simplified eastern subunits of chloropeptin and kistamycin

Abstract Aryl indoles which are building blocks for the synthesis of simplified analogues of macropolypeptides containing an endo carbon-carbon bond are obtained by Suzuki Pd-catalyzed cross coupling reactions involving either haloindoles or indole boronic acids and properly meta substituted phenyl components.

The use of the β-amino-alcohol-n-oxide derivatives in the synthesis of 2,3 or 4-alkyl substituted nh pyrrolidines☆

Abstract Nonstabilized azomethine ylides generated from the various β-amino alcohols N-oxides 13, 17, 23 and 24 undergo [3+2] cycloaddition reactions with unactivated alkenes to afford the corresponding pyrrolidines 14a-g, 18a-g, 25 and 27 in moderate to good yields. These compounds are precursors of NH pyrrolidines substituted in position 2, 3 or 4.

New ‘one-pot’ synthesis of indoles under non-acidic conditions (SRN1 reaction)

Indoles can be obtained directly in high yields under non-acidic conditions by application of the SRN1 reaction to o-iodoaniline.

A new alkylation method of the carbon α to the nitrogen of secondary amines

Abstract A route to the alkylation of the carbon α to the nitrogen of secondary amines 1a,c–g is proposed which is based upon a new and efficient synthesis of oxazolidines 3 from β- hydroxy tertiary amine N -oxides 2 .

A 3+2 cycloaddition route to N-H pyrrolidines devoid of electron-withdrawing groups

N-H pyrrolidines are obtained from intermolecular 3+2 cycloaddition reactions between nonactivated olefins and ylide generated from amine N-oxide 1 structurally designed in such a way as to allow easy dealkylation of the cycloadduct.