Transfer Hydrogenation in Water: Enantioselective, Catalytic Reduction of α-Cyano and α-Nitro Substituted Acetophenones
作者:Omid Soltani、Martin A. Ariger、Henar Vázquez-Villa、Erick M. Carreira
DOI:10.1021/ol1008894
日期:2010.7.2
Catalytic reduction of α-substituted acetophenones under conditions involving asymmetric transfer hydrogenation in water is described. The reaction is conducted in water and open to air, and formic acid is used as reductant.
A process for producing an amine which is characterized by reacting an imine with a nucleophilic compound (except a trialkylsilyl vinyl ether) in the presence of a phosphoric acid derivative represented by the formula (1):
wherein A
1
represents a spacer; X
1
and X
2
represent each independently a divalent nonmetal atom or a divalent nonmetal atomic group; and Y
1
is oxygen or sulfur. The invention provides a process by which amines (particularly optically active amines) useful as intermediates of medicines, agricultural chemicals, or the like can be produced without special post-treatment in high yield at high optical purity; and phosphoric acid derivatives (particularly optically active phosphoric acid derivatives) useful in the production of the amines.
Origin of the asymmetric induction in metallosalen-catalyzed reactions of aldehydes
作者:Wojciech Chaładaj、Janusz Jurczak
DOI:10.1039/b910473a
日期:——
played by the structure of the diamine moiety of salen chromium complexes in determining the catalyst conformational equilibrium and, in consequence, the direction of asymmetricinduction in metallosalen-catalyzed reactions of aldehydes.
Lewisacidcatalysis and nucleophilic carbene catalysis are complementary fundamental concepts to accelerate and control chemical reactions of aldehyde substrates. Their efficient merger has recently been achieved using two separate catalyst species. The present report describes our efforts to develop a cooperative catalyst system which incorporates both features –Lewisacid and nucleophilic NHC –
Rational Design of New Dihydrobenzooxophosphole-Based Lewis Base Organocatalysts
作者:Bo Qu、Lalith P. Samankumara、Anjan Saha、Mac G. Schumer、Zhengxu S. Han、Nizar Haddad、Carl A. Busacca、Nathan K. Yee、Marisa C. Kozlowski、Jinghua J. Song、Chris H. Senanayake
DOI:10.1055/s-0039-1690851
日期:2020.4
A series of new dihydrobenzooxophosphole-based Lewis base organocatalysts were designed and synthesized. They are shown to be effective in trichlorosilane-mediated stereoselective conjugate reductions of C=C bonds. DFT calculations reveal that the strong hydrogen bonds between the amide linker and the chloride on silicon in the transition state contribute to the high reactivity of the catalyst.