Application of a Chiral Scaffolding Ligand in Catalytic Enantioselective Hydroformylation
作者:Amanda D. Worthy、Candice L. Joe、Thomas E. Lightburn、Kian L. Tan
DOI:10.1021/ja107433h
日期:2010.10.27
The synthesis of β-amino-aldehydes has been achieved throughenantioselective hydroformylation of PMP-protected allylic amines. The reaction is accomplished by using a scalemic scaffolding ligand that covalently and reversibly binds to the substrate. These ligands behave like chiral auxiliaries because they are covalently attached to the substrate during hydroformylation; however, similar to traditional
β-氨基醛的合成是通过 PMP 保护的烯丙胺的对映选择性加氢甲酰化来实现的。该反应是通过使用与底物共价可逆结合的鳞片支架配体来完成的。这些配体的行为类似于手性助剂,因为它们在加氢甲酰化过程中共价连接到底物上;然而,与传统的不对称配体类似,它们可以以催化量使用。二取代烯烃的直接加氢甲酰化在温和条件(35 °C 和 50 psi CO/H(2))下进行,Z-烯烃具有优异的对映选择性(高达 93% ee)。
Scope and Mechanism of Tandem Aza-Michael Reaction/Enantioselective Protonation Using a Pd-μ-Hydroxo Complex under Mild Conditions Buffered with Amine Salts
protonation of α‐substituted α,β‐unsaturated carbonylcompounds is described in detail. The key to success is the combined use of a Brønsted basic palladium–μ‐hydroxo complex and amine salts, which allows for the controlled generation of active catalyst and nucleophilic free amines. This catalytic system was applicable to various acceptors and aromatic amines, and the desired β‐amino acid derivatives