| Summary: | 9. Summary We have prepared a set of helical compounds using a modular approach based on 12+2+21 cycloisomerisation of aromatic triynes under cobalt (l) catalysis. [7]helicene-like compound (P,S)-(+)-10, which represents a new structural type of possible liquid crystalline materials, was obtained in an optically pure form on a preparative scale. We have explored the diastereoselective synthesis as a general methodology for the preparation of functionalised helical compounds. A series of methoxy- and bromo-substituted helicene derivatives was successfully prepared with diastereoisomer ratios up to 100:0. ln addition, we have developed a practical synthesis of racemic heptahelicene rac-87. Optically pure heptahelicene (M)-(-)-87 and optically highly enriched (P)-(+)-87 were obtained by resolution of rac-87 by semipreparative HPLC on a chiral column. we have developed an original approach to the synthesis of phosphite ligands bearing helically chiral moieties, which were subsequently used in enantioselective catalysis, namely in hydroformylation reactions and allylic aminations. A series of hydroformylations of styrene, 4-chlorostyrene and vinyl acetate performed with Rh(acac)(co)2 under various conditions revealed that all helically chiral ligands under study afforded good to excellent regioselectivities....
|
|---|
