The rhodium-catalyzed hydroformylation of methyl oleate (MO) with new monodentate phosphoramidite ligands 1a−d is investigated here. The ligands are characterized by lactam rings of different size (four-to seven-membered rings). In mild conditions (synthesis gas pressure: 30 bar, 80 °C), the rhodium catalysts based on the P-azetidinone phosphoramidite 1a gave within 6 h complete conversion and produced mainly methyl 9-and 10-formylstearate (MFS) with 99% chemoselectivity. In the hydrolysis test, phosphoramidite 1a was also the most stable. This was additionally confirmed by density functional theory calculations.
A series of easily prepared bulky P*-chiral diamidophosphites based on (2R,5S)-3-phenyl-1,3-diaza-2-phosphabicyclo[3.3.0]octane and (2R,5S)-3-(p-bromophenyl)-1,3-diaza-2-phosphabicyclo[3.3.0]octane backbones have been designed and developed. Ligands of this type exhibited high enantioselectivities in Pd-catalysed allylic substitution reactions of (E)-1,3-diphenylallyl acetate with NaSO 2 pTol (up to 87 % ee), CH 2 (CO 2 Me) 2 (up to 92 % ee), (C 3 H 7 ) 2 NH (up to 93 % ee) and (CH 2 ) 4 NH (up to 99 % ee). These novel stereoselectors
Synthesis of Phosphorylated Sulfoximines and Sulfinamides and Their Application as Ligands in Asymmetric MetalCatalysis. -Several sulfoximine-and sulfinamide-based phosphorusamides are prepared from inexpensive and easily available educts. Their applications as ligands in allylic substitution reactions and hydrogenation reactions are described. Phosphorous triamide-type ligands (I) derived from (S)-glutamic acid are found to be the most efficient stereoselectors in palladium-catalyzed allylic substitutions, whereas diamidophosphite-type structures such as (II) stemming from (S)-proline are the best ligands in rhodium-catalyzed hydrogenation reactions. -(BENETSKIY, E. B.; BOLM*, C.; Tetrahedron: Asymmetry 22 (2011) 3, 373-378, http://dx.
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