Structural motifs containing contiguous
halide-bearing stereocenters are common in natural products as well
as bioactive molecules. A few successful examples have been reported
in the area of asymmetric vicinal dihalogenation of alkenes for accessing
dihalogenated products; in this report, an alternative generation
method of contiguous halide-bearing stereocenters α,β,γ,δ
relative to carbonyl group in excellent enantioselectivity is proposed
by utilizing a Song’s oligoEG catalyst-catalyzed asymmetric β-elimination.
According to this methodology, a wide range of <i>anti</i>–<i>syn</i>-trihalides and <i>anti</i>–<i>syn</i>–<i>anti</i>-tetrahalides
with high levels of enantioselectivity were synthesized. The synthetic
utility of the contiguous halide-bearing stereocenters was demonstrated
by several transformations. The results of high-resolution mass spectrometry
indicated that the favorable interaction between catalyst and one
of the enantiomers of racemic contiguously multihalogenated ketone
contributed to the original enantioselectivity of dehydrohalogenation.
A deuterium kinetic isotope effect experiment revealed that this β-elimination
reaction proceeds by the <i>E</i>2 mechanism. This strategy
opens a new pathway for the asymmetric synthesis of contiguous halide-bearing
stereocenters of great complexity