Fig. 2: Optimisation of the reaction conditions.

Conditions: 1a (30.1 mg, 50.0 μmol), with indicated catalysts in 5.0 mL toluene. aIsolated yield. bDetermined as (S):(R) by HPLC of isolated product on a chiral stationary phase. cDetermined as (trans):(cis) by 19F NMR analysis of the crude reaction mixture. d2.5 mL instead of 5.0 mL toluene. Optimised conditions in bold.