Synthesis And Stereochemical Behavior Of Dioxa[6]Helicene Derivatives

We constructed a helically chiral dioxa[6]helicene by assembling simple phenol building blocks by a combination of two simple reactions involving oxidative cross-coupling followed by dehydrative cyclization. X-ray analysis and density functional calculations (DFT) revealed that the compound dioxa[6]helicene has a helical structure that undergoes helical inversion rapidly at room temperature. We were able to detect the presence of resolvable helical isomers of (-)-menthyloxycarbonyl derivative of dioxa[6]helicene by recording H-1 NMR spectra below 0 degrees C. The investigations of photo physical properties by cyclic voltammetry, UV/Vis- and fluorescence properties with the aid of time-dependent DFT calculations were undertaken.