391213-68-6Relevant articles and documents
Chemo-enzymatic synthesis of chiral fluorine-containing building blocks
Blaauw, Richard H.,IJzendoorn, Denis R.,Cremers, Jozef G. O.,Rutjes, Floris P. J. T.,Broxterman, Quirinus B.,Schoemaker, Hans E.
, p. 104 - 107 (2007/10/03)
Two complementary strategies for the synthesis of optically active fluorine-containing building blocks have been probed. The first strategy involves either the enzymatic resolution of fluorinated α,α- disubstituted-α-amino acid amides, or the asymmetric h
Application of chiral mixed phosphorus/sulfur ligands to enantioselective rhodium-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation processes
Evans, David A.,Michael, Forrest E.,Tedrow, Jason S.,Campos, Kevin R.
, p. 3534 - 3543 (2007/10/03)
Chiral mixed phosphorus/sulfur ligands 1-3 have been shown to be effective in enantioselective Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of α-acylaminoacrylates in high enantioselectivity (89-97% ee). A similar optimization of the catalyst for the Rh-catalyzed hydrosilylation of ketones showed that ligand 3 afforded the highest enantioselectivities for a wide variety of aryl alkyl and dialkyl ketones (up to 99% ee). A model for asymmetric induction in the hydrogenation reaction is discussed in the context of existing models, based on the absolute stereochemistry of the products and the X-ray crystal structures of catalyst precursors and intermediates.
