Kinetic Resolution of the Acrolein Dimer by Asymmetric Horner‐Wadsworth‐Emmons Reactions

Diastereoselectivities up to 98% de have been reached in kinetic resolutions of the racemic acrolein dimer 1 by reaction with the chiral phosphonates 2. Depending on the choice of substituents on the phosphoryl group (R  CF3CH2, C2H5), either (E)-3 or (Z)-3, both of which are versatile synthetic building blocks, can be obtained as the major product. The dominant isomer for (Z)-3 is the (S) isomer and for (E)-3 the (R) isomer.