Syntéza helikálních molekul a jejich využití v enantioselektivní katalýze

Abstract

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....

8, Závěr S vyuŽitím intramo|eku|ární Í2+2+2] cyk|oizomerace aromatických triynů kata|yzované s|ouěeninami koba|tu (|) by|a připravena série|átek strukturně odvozených od he|icenú sdiastereomerním nadbytkem od 73:27 do 100:0. Látky nesoucí substituenty na heliká|ním ske|etu budou dá|e vyuŽity pro da|šítransformace. Připravené fosfity s heIiká|ní chiraIitou by|y apIikovány v enantioseIektivní kata|ýze, v hydroformy|ačníchreakcích a a||y|ových aminacích, kde by|o dosaŽeno veImi nadějných výs|edků. Heptahe|icen připravený v racemické formě by| s úspěchem rozdě|en na jednot|ivé enantiomery pomocí separace na HPLC s chirá|ní stacionární fází. 17