Highly enantioselective 1,4-addition of arylzinc reagents to 3-arylpropenals catalyzed by a rhodium–binap complex in the presence of chlorotrimethylsilane
摘要:
Asymmetric 1,4-addition of arylzinc chlorides to (E)-3-arylpropenals proceeded with high enantioselectivity in the presence of a rhodium/(R)-binap catalyst and chlorotrimethylsilane to give, after hydrolysis, high yields of the corresponding 3.3-diarylpropanals of 98-99% ee. The presence of the chlorosilane is essential for high yields of the 1,4-addition products. (c) 2006 Elsevier Ltd. All rights reserved.
Highly enantioselective 1,4-addition of arylzinc reagents to 3-arylpropenals catalyzed by a rhodium–binap complex in the presence of chlorotrimethylsilane
摘要:
Asymmetric 1,4-addition of arylzinc chlorides to (E)-3-arylpropenals proceeded with high enantioselectivity in the presence of a rhodium/(R)-binap catalyst and chlorotrimethylsilane to give, after hydrolysis, high yields of the corresponding 3.3-diarylpropanals of 98-99% ee. The presence of the chlorosilane is essential for high yields of the 1,4-addition products. (c) 2006 Elsevier Ltd. All rights reserved.
Asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated aldehydes proceeded in the presence of a rhodium catalyst (3 mol %) coordinated with a chiral diene ligand ((R,R)-Bn-bod*) to give the corresponding β-arylaldehydes with perfect 1,4-selectivity and with 88–97% enantioselectivity.
Chiral dihydrobenzo[1,4]oxazines as catalysts for the asymmetric transfer-hydrogenation of α,β-unsaturated aldehydes
作者:Christian Ebner、Andreas Pfaltz
DOI:10.1016/j.tet.2011.10.051
日期:2011.12
A new class of organocatalysts based on the structure of 2,3-dihydrobenzo[1,4]oxazine was prepared and applied in the enantioselective transfer-hydrogenation of α,β-unsaturatedaldehydes with Hantzsch ester as hydride donor. These catalysts proved to be particularly effective for the conjugate reduction of β,β-diaryl-substituted acrylaldehydes leading to saturated aldehydes bearing a stereogenic center
Asymmetric Synthesis of 3,3-Diarylpropanals with Chiral Diene−Rhodium Catalysts
作者:Jean-François Paquin、Christian Defieber、Corey R. J. Stephenson、Erick M. Carreira
DOI:10.1021/ja053270w
日期:2005.8.1
A general route to enantioenriched 3,3-diarylpropanals is presented. These useful building blocks are prepared via an asymmetric rhodium-catalyzed conjugate addition of arylboronic acids to cinnamaldehyde derivatives in the presence of chiral dienes. The addition of both electron-poor as well as electron-rich boronic acids proceeds smoothly with various enals in 63-90% yield with high enantioselectivities (89-93% ee).