L. Lardicci

Direct ni mediated synthesis of ketones from acyl bromides and grignard reagents

Abstract a catalytic amount of NidppeCl 2 converts an acyl bromide directly into ketones at 0 °C in THF in the presence of a Grignard reagent. The described procedure represents a useful way to afford dialkyl, diaryl or alkyl aryl ketones as well as 1,2-diketones. In the adopted reaction conditions double bonds, esters and ketones are unaffected.

Chiral ligands containing heteroatoms. III. Enantioselective ketone reductions using tin(II) organometallic systems from chiral piperazines

Abstract Chiral reducing agents were prepared from stannous chloride, optically active piperazines as ligands and diisobutylaluminium hydride; these complexes were effectively employed in the asymmetric reduction of prochiral ketones.

Reactions of 3-alkyl- and 3,3-dialkyl-1-bromoallenes with organocuprates: Effects of the nature of the cuprate reagent on the regio- and stereoselectivity

Abstract Organocuprates induce 1,3- and direct substitution in 3-alkyl- and 3,3-dialkyl-1-bromo-1,2-dienes leading respectively to either terminal acetylenes or allenic hydrocarbons. The nature of the cuprate exerts a prominent role in determining both the regio- and the stereochemistry of these reactions.

Carbon-halogen bond activation by nickel catalyst: Synthesis of alkenes, from 1,2-dihalides

Abstract Unsaturated hydrocarbons can easily be prepared in a few seconds starting from 1,2 dibromides in the presence of a catalytic amount of Nickel diphenylphosphinoethane dichloride (NidppeCl2) and tri.n.butyl tin hydride, (TBTH) at room temperature. The dependencie of the nature of starting dihalides is investigated.

Thermal racemization of some organometallic compounds containing elements of the first, second and third group of the periodic table and optically active alkyl groups

Abstract The chemical reactivity of organometallic compounds containing a tertiary carbon atom in the β position with respect to the metal atom, was studied by investigation of the thermal racemization of some organometallic compounds of Li, Mg, Be, Zn, Cd, B and Al containing optically active alkyl groups. At a temperature of 100° only the 2-methylbutyl derivatives of Be, B and Al racemize at an appreciable rate. When the asymmetric carbon atom is in the γ or δ position with respect to the metal atom, no racemization was observed. The influence of solvents on the optical activity decay rate and a reasonable mechanism of the thermal racemization of the investigated organometallic compounds are discussed.

Copper catalyzed aminolysis of bromoallenes as a new efficient route to propargylamines

Abstract An efficient procedure of general applicability for the synthesis of secondary and tertiary propargylamines by copper mediated aminolysis of 1-bromo-1,2-dienes is described.

Alkylmetal asymmetric reduction. XVI. Tris(cis-myrtanyl)gallium: An unusual organometallic compound as enantioselective reducing agent of ketones

Abstract Tris[[(1S,2R)-6,6-dimethylbicyclo[3.1.1]heptan-2-yl] methyl]-gallium was found to react with ketones above room temperature: optically active reduction carbinols were recovered as main products.

Metal catalysis in organic reactions. X. Nickel-catalyzed dimerization of 1-alkynes to 1,3-dialkylbutenynes

An efficient method for the selective synthesis of 1,3-dialkylbutenynes is described via reaction between terminal acetylenes and isolated diisobutylzinc in the presence of a nickel catalyst.

Nickel Mediated Conversion of Acyl Halides in Aldehydes

Abstract Aldehydes are obtained from acyl halides employing stoichiometric tri n.butyl tin hydride (TBTH) and catalytic nickeldiphenylphosphinoethane dichloride (NidppeCl 2 ), at room temperature.

NICKEL MEDIATED FLASH ISOMERIZATION - A NEW APPROACH TO 1,4-BUT-1-ENE DIOL DERIVATIVES

Abstract Fast isomerization of cis 1,4-but-2-endiol derivatives ( 1 ) to 1,4-but-1-endiol derivatives ( 2 ) was carried out in mild conditions. The activity of the proposed Ni-hydride species is closely correlated with the nature of the protecting groups of the alcoholic functions of 1 , which are also responsible for the regio and stereo chemical aspects of the reaction.