479423-51-3Relevant academic research and scientific papers
Divergent Stereoinduction Mechanisms in Urea-Catalyzed Additions to Imines
Wenzel, Anna G.,Lalonde, Mathieu P.,Jacobsen, Eric N.
, p. 1919 - 1922 (2003)
Catalyst structure/enantioselectivity profiles for the asymmetric Strecker and Mannich reactions were obtained through systematic variation of each modular component of the catalyst. Although the thiourea derivative 1 afforded optimal results in both reactions (97-98% ee), the structural elements responsible for stereoinduction were found to be fundamentally different. Insights gleaned from these studies led to the development of a new generation catalyst for the Mannich reaction that promotes the asymmetric silyl ketene acetal addition to N-Boc benzaldimine in 94% ee. The new catalyst is a simple amino acid derivative possessesing less than half the molecular weight and two fewer stereocenters relative to 1.
Disulfonimide-catalyzed asymmetric synthesis of β3-amino esters directly from N-Boc-amino sulfones
Wang, Qinggang,Leutzsch, Markus,Van Gemmeren, Manuel,List, Benjamin
, p. 15334 - 15337 (2013/11/06)
An asymmetric Mannich reaction of silyl ketene acetals with N-Boc-amino sulfones has been developed. A chiral disulfonimide efficiently catalyzes both the in situ generation of the corresponding N-Boc imines and the asymmetric Mannich reaction with excellent yields and enantioselectivities. Kinetic studies confirm a proposed stepwise mechanism.
Asymmetric catalytic Mannich reactions catalyzed by urea derivatives: Enantioselective synthesis of β-aryl-β-amino acids
Wenzel, Anna G.,Jacobsen, Eric N.
, p. 12964 - 12965 (2007/10/03)
Highly enantioselective addition reactions between silyl ketene acetals and N-Boc aldimines are catalyzed by the thiourea-based catalyst 1c. Extraordinary scope is observed in this methodology with regard to the imine substrate, with aryl and heteroaromatic derivatives generally affording nearly quantitative yields of β-amino ester product in up to 98% enantioselectivity. Copyright
