Rh(2)(S-PTTL)(3)TPA-A Mixed Ligand Dirhodium(II) Catalyst for Enantioselective Reactions of ?-Alkyl-?-Diazoesters.

ABSTRACT: Herein we report the synthesis of the mixed ligand paddlewheel complex dirhodium(II) tris[N-phthaloyl-(S)-tert-leucinate] triphenylacetate, Rh(2)(S-PTTL)(3)TPA, the structure of which bears similarity to the chiral crown complex Rh(2)(S-PTTL)(4). Rh(2)(S-PTTL)(3)TPA engages substrate classes (aliphatic alkynes, silylacetylenes, ?-olefins) that are especially challenging in intermolecular reactions of ?-alkyl-?-diazoesters, and catalyzes enantioselective cyclopropanation, cyclopropenation, and indole C-H functionalization with yields and enantioselectivities that are comparable or superior to Rh(2)(S-PTTL)(4). Mixing ligands on paddlewheel complexes offers a versatile handle for diversifying catalyst structure and reactivity. The results described herein illustrate how mixed ligand catalysts can create new opportunities for the optimization of catalytic asymmetric processes.

SUBMITTER: Boruta DT 

PROVIDER: S-EPMC3486924 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature