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Resolution of a Configurationally Stable Hetero[4]helicene |
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| Authors: | Michela Lupi Martina Onori Stefano Menichetti Sergio Abbate Giovanna Longhi Caterina Viglianisi |
| Affiliation: | 1.Department of Chemistry “Ugo Schiff” (DICUS), University of Florence, Via della Lastruccia 13, Sesto Fiorentino (FI), 50019 Florence, Italy; (M.L.); (M.O.); (S.M.);2.Department of Molecular and Translational Medicine (DMMT), University of Brescia, V.le Europa 11 Brescia (BS), 25121 Brescia, Italy; (S.A.); (G.L.) |
| Abstract: | We have developed an efficient chemical resolution of racemic hydroxy substituted dithia-aza[4]helicenes (DTA[4]H) 1(OH) using enantiopure acids as resolving agents. The better diastereomeric separation was achieved on esters prepared with (1S)-(−)-camphanic acid. Subsequent simple manipulations produced highly optically pure (≥ 99% enantiomeric excess) (P) and (M)-1(OH) in good yields. The role of the position where the chiral auxiliary is inserted (cape- vs. bay-zone) and the structure of the enantiopure acid used on successful resolution are discussed. |
| Keywords: | heterohelicene chirality resolution enantiomers chiroptical screw-shaped compounds |