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.

Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Flemingovo nám 2 16610 Prague 6 Czech Republic

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Stereocontrolled Synthesis of Chiral Helicene-Indenido ansa- and Half-Sandwich Metal Complexes and Their Use in Catalysis

Synthesis of a Helical Phosphine and a Catalytic Study of Its Palladium Complex