Atroposelective Access to Oxindole-Based Axially Chiral Styrenes via the Strategy of Catalytic Kinetic Resolution

Atroposelective
synthesis of axially chiral molecules has attracted
substantial attention from chemists because of the importance of such
molecules. However, catalytic asymmetric synthesis of axially chiral
styrenes or vinyl arenes is underdeveloped and challenging due to
the low rotational barrier and weak configurational stability of such
molecules. Therefore, the development of powerful strategies for the
catalytic atroposelective synthesis of axially chiral styrenes or
vinyl arenes is of great importance. In this work, we have accomplished
the first atroposelective access to oxindole-based axially chiral
styrenes by the strategy of catalytic kinetic resolution, and this
strategy offered two kinds of oxindole-based axially chiral styrene
derivatives in good diastereoselectivities (up to 94:6 dr) and excellent
enantioselectivities (up to 98% ee) with high selectivity factors
(S up to 106). This strategy not only provides easy
access to oxindole-based axially chiral styrenes but also offers a
robust method for synthesizing bisamide derivatives bearing both axial
and central chirality. More importantly, this strategy has added a
new class of members to the atropisomeric family, especially to the
family of axially chiral styrenes.