Application of SDP Ligands for Pd-Catalyzed Allylic Alkylation

✍ Scribed by Jian-Hua Xie; Hai-Feng Duan; Bao-Min Fan; Xu Cheng; Li-Xin Wang; Qi-Lin Zhou

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 145 KB
• Volume: 346
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.200404003

✦ Synopsis

Abstract

Chiral spiro diphosphines (SDP) are efficient ligands for the Pd‐catalyzed asymmetric allylic alkylation of 1,3‐diphenyl‐2‐propenyl acetate with dimethyl malonate and related nucleophiles. The newly synthesized ligand DMM‐SDP (1e) with 3,5‐dimethyl‐4‐methoxy groups on the P‐phenyl rings of the phosphine shows the highest enantioselectivity (up to 99.1% ee). Diethylzinc as a base is critical for obtaining high enantioselectivity in the allylic alkylation using β‐dicarbonyl nucleophiles. The structure of catalyst [PdCl~2~((S)‐SDP)] was determined by single crystal X‐ray diffraction. The SDP ligands create an effective asymmetric environment around the palladium, resulting in high enantioselectivities for the asymmetric allylic alkylation reaction