202530-97-0Relevant academic research and scientific papers
Titanocene-catalyzed asymmetric ketone hydrosilylation: The effect of catalyst activation protocol and additives on the reaction rate and enantioselectivity
Yun, Jaesook,Buchwald, Stephen L.
, p. 5640 - 5644 (1999)
The efficient asymmetric hydrosilylation of ketones with a chiral titanocene catalyst has been realized. In this procedure, (R,R)-ethylenebis(tetrahydroindenyl) titanium difluoride (1) was used as the precatalyst, and alcohol additives were employed. Arom
Asymmetric hydrosilylation of ketones using trans-chelating chiral peralkylbisphosphine ligands bearing primary alkyl substituents on phosphorus atoms
Kuwano, Ryoichi,Sawamura, Masaya,Shirai, Junya,Takahashi, Masatoshi,Ito, Yoshihiko
, p. 485 - 496 (2007/10/03)
Asymmetric hydrosilylation of simple ketones with diphenylsilane proceeded at -40 °C in the presence of a rhodium complex (0.001 - 0.01 molar amount) coordinated with a trans-chelating chiral bisphosphine ligand bearing linear alkyl substituents on the phosphorus atoms, (R,R)-(S,S)-Et-, Pr-, or BuTRAP, giving the corresponding optically active (S)- secondary alcohols with up to 97% ee. The asymmetric hydrosilylation using TRAP ligands with bulkier P-substituents resulted in much lower enantioselectivities. The EtTRAP-rhodium catalyst was also effective for asymmetric hydrosilylation of keto esters with a coordination site for a rhodium atom (up to 98% ee). Optically active symmetrical diols were obtained with up to 99% ee from the corresponding diketones via the asymmetric reduction using 2.5 molar amounts of diphenylsilane.
Epoxides, process for their preparation and their use for the preparation of perfuming ingredients
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, (2008/06/13)
Epoxides of formula STR1 having a cyclanic (1R) configuration, the group in position 2 being in a trans configuration and the epoxy group being in a cis configuration with respect to that in position 1 of the ring, and in which R represents a lower alkyl group and R1 represents a saturated or unsaturated, linear or branched hydrocarbon group having from 1 to 8 carbon atoms, are useful molecules for the preparation of very prized perfuming ingredients. A process for the preparation of the opoxides (I) is also described.
