934239-67-5Relevant academic research and scientific papers
Synthesis and resolution of a new helically chiral azahelicene
Aloui, Faouzi,Abed, Riadh El,Marinetti, Angéla,Hassine, Béchir Ben
, p. 4092 - 4095 (2008)
Helically chiral azahexahelicene 3 was prepared in four steps using the Mizoroki-Heck coupling followed by classical oxidative photodehydrocyclisation. Resolution of this new chiral system was achieved through separation by HPLC providing (-)- and (+)-3 in high optical purity. The absolute configurations of (-)- and (+)-3 were assigned as M and P, respectively, by means of circular dichroism. Each of the hexacyclic systems (M)-(-)- and (P)-(+)-3 was reacted with boron tribromide to provide the corresponding helical pyridophenols in good yields.
Helicenes with embedded phosphole units in enantioselective gold catalysis
Yavari, Keihann,Aillard, Paul,Zhang, Yang,Nuter, Frédérick,Retailleau, Pascal,Voituriez, Arnaud,Marinetti, Angela
, p. 861 - 865 (2014)
This paper discloses the first uses of phosphahelicenes as chiral ligands in transition-metal catalysis. Unlike all known helical phosphines used so far in catalysis, the phosphorus function of phosphahelicenes is embedded in the helical structure itself. This crucial structural feature originates unprecedented catalytic behaviors and efficiency. An appropriate design and fine tuning allowed both high catalytic activity and good enantiomeric excesses to be attained in the gold promoted cycloisomerizations of N-tethered 1,6-enynes and dien-ynes. A twist of gold: Phosphahelicenes were for the first time used as chiral ligands in transition-metal catalysis. Unlike all helical phosphines used so far in catalysis, the phosphorus atom of phosphahelicenes is embedded within the helical structure (see scheme). Structural design allowed both high catalytic activity and good ee values to be attained in gold-promoted cycloisomerizations of N-tethered 1,6-enynes and dienynes. Copyright
Synthesis and characterization of new hexahelicene derivatives
Aloui, Faouzi,El Abed, Riadh,Marinetti, Angéla,Ben Hassine, Béchir
, p. 2017 - 2020 (2007)
The synthesis and structural characterization of a new hexahelicene derivative 2 is reported. This compound features a new type of structure bearing a bromine atom and a methoxy group. Suitable crystals of the latter indicate that its conformation closely
