Asymmetric transition metal-catalyzed alkyl addition to imines with chiral phosphine ligands
El Hajjaji, Samir (2010) Asymmetric transition metal-catalyzed alkyl addition to imines with chiral phosphine ligands. PhD thesis, University of Nottingham.
The research project presented in this thesis deals with the development of the alkylation of protected aldimines using organoaluminium and organozinc compounds as alkylating agents. To this end, efforts have been focused into the methylation reaction using trimethylaluminium and dimethylzinc. It was hoped to establish promising conditions using the methylate group and then to extend the catalytic system to other interesting nucleophiles. In the case of organoaluminium alkylation the reaction was extended to other nucleophiles, namely to the allyl and propargyl groups. The identificaton of suitable metal catalysts as well as diphosphine ligands was carried out by means of extensive high throughput screening. On the one hand [IrCl(COD)]2 proved to be very efficient when associated to AlMe3 or DABAL-Me3 in the non-enantioselective 1,2-addition reactions to aldimines (100% conversion in 3 h). On the other hand, [RhCl(COD)]BF4 was found to be able to efficiently catalyse the enantioselective 1,2-addition of Me2Zn to aldimine substrates (100% conversion in 3 h - up to 99% e.e.).
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