Construction of Acyclic Vicinal All-Carbon Quaternary and Tertiary Carbon Stereocenters via a Stereoselective Claisen Rearrangement

The
selective construction of neighboring congested stereocenters
in an acyclic setting bearing an all-carbon quaternary stereocenter
is one of the important challenges in stereoselective synthesis. [3,3]-Sigmatropic
rearrangements are powerful reactions with potential for the stereoselective
construction of such arrays due to their intrinsic stereochemical
nature associated with the well-defined and highly predictable transition
state. However, such types of transformations are very difficult to
catalyze in terms of selectivity and complexity. Herein, we outlined
a diastereoselective Claisen rearrangement in the presence of a CuI catalyst and a tricoordinated ligand environment that enables
complete stereocontrol, leading to chiral alcohols, amides, and oxazolines
with vicinal all-carbon quaternary-tertiary or tertiary-tertiary stereodiads.