1 research outputs found
An Ultimate Stereocontrol in Asymmetric Synthesis of Optically Pure Fully Aromatic Helicenes
The
role of the helicity of small molecules in enantioselective
catalysis, molecular recognition, self-assembly, material science,
biology, and nanoscience is much less understood than that of point-,
axial-, or planar-chiral molecules. To uncover the envisaged potential
of helically chiral polyaromatics represented by iconic helicenes,
their availability in an optically pure form through asymmetric synthesis
is urgently needed. We provide a solution to this problem present
since the birth of helicene chemistry in 1956 by developing a general
synthetic methodology for the preparation of uniformly enantiopure
fully aromatic [5]-, [6]-, and [7]helicenes and their functionalized
derivatives. [2 + 2 + 2] Cycloisomerization of chiral triynes combined
with asymmetric transformation of the first kind (ultimately controlled
by the 1,3-allylic-type strain) is central to this endeavor. The point-to-helical
chirality transfer utilizing a traceless chiral auxiliary features
a remarkable resistance to diverse structural perturbations