1040140-91-7Relevant academic research and scientific papers
Preparation of C3-symmetric homochiral syn-trisnorbornabenzenes through regioselective cyclotrimerization of enantiopure iodonorbornenes
Reza, A. F. G. Masud,Higashibayashi, Shuhei,Sakurai, Hidehiro
, p. 1329 - 1337 (2009)
C3-symmetric homochiral (-)-syn-trisoxonorbornabenzene 1 possessing a rigid cup-shaped structure was synthesized through a novel regioselective cyclotrimerization of enantiopure iodonorbornenes catalyzed by palladium nanoclusters. The yield of
Trimethylsumanene: Enantioselective synthesis, substituent effect on bowl structure, inversion energy, and electron conductivity
Higashibayashi, Shuhei,Tsuruoka, Ryoji,Soujanya, Yarasi,Purushotham, Uppula,Sastry, G. Narahari,Seki, Shu,Ishikawa, Takeharu,Toyota, Shinji,Sakurai, Hidehiro
, p. 450 - 467 (2012)
C3 symmetric chiral trimethylsumanene was enantioselectively synthesized through Pd-catalyzed syn-selective cyclotrimerization of an enantiomerically pure iodonorbornenone, ring-opening/closing olefin metathesis, and oxidative aromatization where the sp3 stereogenic center was transmitted to the bowl chirality. Chiral HPLC analysis/resolution of the derivatives were also achieved. Based on theoretical calculations, the columnar crystal packing structure of sumanene and trimethylsumanene was interpreted as due to attractive electrostatic or CH-π interaction. According to the experimental and theoretical studies, the bowl depth and inversion energy were found to increase on methylation for sumanene in contrast to corannulene. Dissimilarities of the effect of methylation on the bowl structure and inversion energy of sumanene and corannulene were ascribed to differences in steric repulsion. A double-well potential model was fitted to the bowl structureinversion energy correlation of substituted sumanenes, with a small deviation. The effects of various substituents on the sumanene structure and bowl-inversion energy were analyzed by density functional theory calculations, and it was shown that the bowl rigidity is controlled by a combination of electronic and steric effects of the substituents. The electron conductivity of trimethylsumanene was investigated by time-resolved microwave conductivity method, compared with that of sumanene.
Asymmetric synthesis of a chiral buckybowl, trimethylsumanene
Higashibayashi, Shuhei,Sakurai, Hidehiro
supporting information; experimental part, p. 8592 - 8593 (2009/02/02)
The first asymmetric synthesis of a chiral buckybowl, a C3 symmetric (C)-8,13,18-trimethylsumanene (1), was achieved by employing a synthetic strategy that translates chirality at sp3 centers into bowl chirality. The synthesis features a syn selective cyclotrimerization of an enantiopure halonorbornene derivative, tandem ring-opening/closing olefin metathesis reactions, and DDQ oxidation at low temperature. The bowl-to-bowl inversion energy of 1 was determined as 21.6 kcal/mol by circular dichroism spectra measurement. Copyright
