Synthesis of [7]Helicene Enantiomers and Exploratory Study of Their Conversion into Helically Chiral Iodoarenes and Iodanes

Chemistry. 2019 Feb 21;25(11):2852-2858. doi: 10.1002/chem.201805761. Epub 2019 Jan 29.

Abstract

The facile and convenient preparation of both enantiomers of a [7]helicene scaffold from inexpensive (l)-(+)-tartaric acid and 4-methylstyrene is described. These helical structures were transformed into bis-iodinated ether derivatives in order to explore their potential as precursors of novel chiral organoiodane reagents or as iodoarene pre-catalysts. Promising results were obtained in hydroxylative phenol dearomatization/[4+2] cycloaddition cascade and dearomative spirolactonization reactions with encouraging enantiomeric excesses.

Keywords: asymmetric synthesis; dearomatization; helicenes; iodanes; photocyclization.