Substrate control: asymmetric induction by molecular framework in cyclic systems[ edit ] Cyclic molecules often exist in much more rigid conformations than their linear counterparts. Once again, chelation is prevented, and dipole opposition causes a reversal in facial selectivities, leading to the enantiomeric anti-aldol product.
A structure for this complex will also be displayed on the right by clicking on the original structure. It should be noted that the anti-configuration of substituents in aldehyde I mutually reinforce Felkin-Ahn control, especially with the E-enolate.
Felkin—Anh and polar Felkin—Anh model[ edit ] Selectivity in nucleophilic additions to chiral aldehydes is often explained by the Felkin—Anh model  see figure.
Cram's rule[ edit ] The Cram's rule of asymmetric induction developed by Donald J. Analogous Mukaiyama aldol reactions are shown in the following diagram. In this case the nucleophilic addition reaction happens at the face where the hydrogen the small group is, producing the R, R -isomer as the major product.
Addition of tert-butylhydroperoxide and an allylic alcohol results in the displacement of two more isopropyl alcohols and the formation of a new reactive catalyst complex.