Asymmetric -alkylation

CHIRAL CATALYST-INDUCED ALDEHYDE ALKYLATION ASYMMETRIC NUCLEOPHILIC ADDITION... [Pg.107]

Chiral Catalyst-Induced Aldehyde Alkylation Asymmetric... [Pg.513]

Ci-TunePhos-modified Pd catalysts have found applications in allylic asymmetric alkylations, asymmetric hydrogenations of a- and /3-ketoesters <2006SL1169, 2000JOC6223>, allylphthalimides <2005AGE4933>, enol acetates <2002OL4495>, and asymmetric cycloadditions <2005TL8213>. [Pg.362]

Keywords Phase transfer. Chiral ligand. Chiral base, Allylic alkylation. Cinchonine, Enolate alkylation. Asymmetric deprotonation. Asymmetric arylation. Radical alkylation... [Pg.1201]

Nemoto and Hamada [50] has described the development of a new class of chiral phosphorus ligand - aspartic acid-derived P-chirogenic diaminophosphine oxides, DIAPHOXs - and their application to several Pd-catalyzed asymmetric allylic substitution reactions. Pd-catalyzed asymmetric allylic alkylation was initially examined in detail using diaminophosphine oxides 77, resulting in the highly enantioselective construction of quaternary stereocenters. With the use of the Pd-DIAPHOX catalyst system, asymmetric allylic alkylation, asymmetric allylic amination, and enantioselective construction of quaternary carbons were achieved with high ee (up to 97-99% in many cases) (Scheme 24). [Pg.179]

One-carbon Homologations. SEM-Cl can be used as a formaldehyde equivalent, which upon alkylation affords, directly, a protected hydroxyl. SEM-Cl does not suffer from some of the handling liabilities of formaldehyde (e.g., the need for cracking or the use of aqueous solutions) and as such has shown specific promise in the area of asymmetric alkylations. Asymmetric alkylations of enolates have been accomplished via the employment of chiral auxiliaries including oxazolidinones (eq 26) and RAMP/SAMP hydrazones. Furthermore, Schultz and co-workers have utilized SEM-Cl to trap chiral enolates derived from Birch reductions (eq 27). ... [Pg.631]

Keywords Allylic alkylation Asymmetric catalysis Decarboxylation Enolate a-alkylation Palladium catalysis PHOX ligands Quaternary stereocenters... [Pg.281]