Skip to main content
. Author manuscript; available in PMC: 2021 Aug 12.
Published in final edited form as: J Am Chem Soc. 2020 Jul 30;142(32):13917–13933. doi: 10.1021/jacs.0c06243

Table 2.

Effects of Solvation and Ligand Electronics on Enantioselectivity

graphic file with name nihms-1656743-t0019.jpg
Entry Ligand Solvent [ε] ee (%)a Yield 22 (%)b ΔGeqc
1 (S)-t-BuPHOX THF [7.4] 23 99 1.8
2 (S)-t-BuPHOX PhMe [2.4] 28 96 24.0
3 (S)-(CF3)3-t-BuPHOX PhMe [2.4] 32 90 31.0
4 (S)-(CF3)3-t-BuPHOX 2:1 MeCy/PhMe [2.1] 36 69d 35.2
graphic file with name nihms-1656743-t0020.jpg
a

Obtained by chiral SFC.

b

Determined by 1H NMR with respect to internal standard.

c

Change in free energy (in kcal/mol, 1 M standard state) from square pyramidal enolate to free ions.

d

34% 20 remaining after 12 h (1H NMR with respect to internal standard).