Fig. 4: Computational analysis of proline-catalzyed aldol reactions of α-haloaldehydes.
a Transition state structures (R)-TS1O-F, (S)-TS2O-F and (S)-TS3O-F for l-proline-catalyzed aldol reactions of dioxanone 13 with (R)- or (S)-2-fluoropentanal. Oxygen atoms are colored in red, fluorine atoms are colored in green. b Transition state structures (R)-TS1O-Cl, (S)-TS2O-Cl, and (S)-TS3O-Cl for l-proline-catalyzed aldol reactions involving dioxanone 13 with (R)- or (S)-2-chloropentanal. DFT calculations were performed using IEFPCM(DCM)M06-2X/6-311++G(2d,2p)//IEFPCM(DCM)M06-2X/6-31+G(d,p) level of theory. The α-chloro and α-fluoroaldehydes are colored in blue.
