Chiral Bisarsine-Ligand: Synthesis and Applications in Palladium-Catalyzed Asymmetric Allylic Alkylations

PAULA M. UBERMAN; MINO R. CAIRA; SANDRA E. MARTIN

ORGANOMETALLICS

AMER CHEMICAL SOC

Lugar: Washington; Año: 2013 vol. 32 p. 3220 - 3226

0276-7333

The new chiral bisarsine-ligand1,2-bis-N-[2?-diphenylarsinobenzoyl]-1(R),2(R)-diaminecyclohexane (BiAsBA, 3) based on the backbone of the Trost modular ligand (TML) was synthesized in three steps. A useful approach to introduce the -AsPh2 group on arsine ligands by Pd-catalyzed arsination was used. The molecular structure and configuration of BiAsBA ligand was determined by single-crystal X-ray crystallography. In the asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate complete-to-very high conversion and modest enantioselectivity were achieved. Despite the low enantioselectivity obtained, the bisarsine ligand BiAsBA showed significant potential, since it provided higher ee value than the phosphorus homologous ?Trost Standard Ligand? (TSL) with the same substrate.