Asymmetric induction with organocuprates

Asymmetric induction in the conjugate addition of achiral residues to a,(3-unsaturated carbonyl compounds can be achieved with chiral ligand-modified organocuprate reagents. Early experiments, em-... 

The reactions of organocuprates with allylic halides and esters have been widely studied [624a]. The introduction of chiral leaving groups on the electrophile aUows useful levels of asymmetric induction. Gais and coworkers [519] have used chiral sulfoximines 1.150. Isomerization of these sulfoximines, followed by... 

Other asymmetric substrates can be used with organocuprates. One example is Scolastico s report that reaction of 470 with di-n-butylcuprate gave a 70% yield of 471 (78-98 % ee). 32 Using this auxiliary, alkylated ester 471 was converted to aldehyde 472 in 80% yield with 91% asymmetric induction. 32... 

Boron has been protected from nucleophilic attack by intramolecular coordination in asymmetric Michael additions of organocuprates to acryloyl and vinylsulfonyl dioxazaborocines [20]. With an optically pure aminodiol, the enantiomeric purity was determined after oxidation of the carbon-boron bond. The greatest degree of asymmetric induction observed with a sulfone derivative was rationalized by an exo-approach of the organometaUic reagent (Scheme 9.8). 

---