223561-11-3Relevant academic research and scientific papers
Applications of 4,4′-Me3Si2-BINAP in transition-metal-catalyzed asymmetric carbon-carbon bond-forming reactions
Ogasawara, Masamichi,Ngo, Helen L.,Sakamoto, Takeshi,Takahashi, Tamotsu,Lin, Wenbin
, p. 2881 - 2884 (2005)
(Chemical Equation Presented) A recently developed BINAP derivative with trimethylsilyl substituents on the 4- and 4′-positions of the binaphthyl skeleton, 2,2′-bis-(diphenylphosphino)-4,4′-bis(trimethylsilyl)-1, 1′-binaphthyl (tms-BINAP), was used in a variety of transition-metal- catalyzed asymmetric carbon-carbon bond-forming reactions. In π-allylpalladium-mediated reactions, tms-BINAP gave better enantioselectivity than the unsubstituted BINAP, and the origin of the improved enantioselectivity was gained from an X-ray structural study of [Pd(η3-C 3H5)((R)-tms-BINAP)]ClO4.
Pd-catalyzed enantioselective synthesis of quaternary α-amino acid derivatives using a phenylalanine-derived P-chirogenic diaminophosphine oxide
Nemoto, Tetsuhiro,Harada, Teisuke,Matsumoto, Takayoshi,Hamada, Yasumasa
, p. 6304 - 6307 (2008/02/10)
A Pd-catalyzed enantioselective synthesis of quaternary α-amino acid derivatives using a phenylalanine-derived P-chirogenic diaminophosphine oxide is described. Asymmetric allylic substitution using acyclic β-keto esters with a nitrogen functional group at the α-carbon as prochiral nucleophiles proceeded in the presence of 5 mol % of Pd catalyst, 10 mol % of chiral diaminophosphine oxide 1j, BSA, and appropriate additives, affording the corresponding quaternary α-amino acid derivatives in excellent yield and in up to 92% ee.
Development of a new class of chiral phosphorus ligands: P-chirogenic diaminophosphine oxides. A unique source of enantioselection in Pd-catalyzed asymmetric construction of quaternary carbons
Nemoto, Tetsuhiro,Masuda, Takamasa,Matsumoto, Takayoshi,Hamada, Yasumasa
, p. 7172 - 7178 (2007/10/03)
We have recently developed a new class of chiral phosphorus ligands: P-chirogenic diaminophosphine oxides. These pentavalent phosphorus compounds have been successfully applied to Pd-catalyzed asymmetric construction of tertiary and quaternary carbons. The actual ligand structure was the trivalent phosphorus species 17, which was generated in situ by BSA-induced P(V) to P(III) transformation of 6, the preligand. Detailed mechanistic studies, including asymmetric amplification and initial rate kinetics, revealed that complex 18 [Pd-17 (1:2) complex] was the active catalyst. The important function of the nitrogen atom on the sidearm in the ligands was also clarified. The source of enantioselection in the construction of asymmetric quaternary carbons was the secondary ligand substrate interaction mediated by N-Zn coordination.
