Synthesis and crystal structure of chiral bifunctional helicenes with π-deficient pyridine and π-excessive thiopene units

Article abstract of DOI:10.1016/0040-4039(96)01278-6

Both enantiomers of new bifunctional helicenes constructed from π-excessive 2-(hydroxymethyl)thiophene and π-deficient pyridine rings have been prepared using (1R, 2S, 3R, 4S)-3-amino-2-hydroxybornane as a chiral auxiliary. The X-ray crystal structure reveals the intermolecular hydrogen bond between the hydroxy group of the helicene and the pyridine nitrogen atom of the adjacent molecule. The non-bonded distance between the nitrogen atom and the oxygen atom is 2.72 A, and the interplanar angle between the terminal rings is 45.3°.