tertiary C-O bond via asymmetric allylicsubstitution of racemic vinylethylene carbonates with water and alcohols has been developed. Under the cooperative catalysis system of an in situ generated chiral palladium complex and boron reagent in mild conditions, the process allowed rapid access to valuable tertiary alcohols and ethers in high yields with complete regioselectivities and high enantioselectivities
已经开发了一种通过外消旋乙烯基碳酸亚乙酯与水和醇的不对称烯丙基取代对映选择性构建叔 CO 键的有效方法。在温和条件下原位生成的手性钯配合物和硼试剂的协同催化系统下,该过程允许以高产率快速获得有价值的叔醇和醚,具有完整的区域选择性和高对映选择性。该协议代表了与作为氧供体的水直接对映选择性形成三级 CO 键的第一个例子。该过程的合成效用已通过将产品加工成生物相关制剂的关键中间体来证明,
Palladium‐Catalyzed Decarboxylative Cycloaddition of Vinylethylene Carbonates with Formaldehyde: Enantioselective Construction of Tertiary Vinylglycols
An efficient method for the enantioselectiveconstruction of tertiaryvinylglycols through a palladium‐catalyzed asymmetric decarboxylativecycloaddition of vinylethylenecarbonates with formaldehyde was developed. By using a palladium complex generated in situ from [Pd2(dba)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the process allows conversion of racemic
Highly Enantioselective [5 + 2] Annulations through Cooperative N-Heterocyclic Carbene (NHC) Organocatalysis and Palladium Catalysis
作者:Santanu Singha、Tuhin Patra、Constantin G. Daniliuc、Frank Glorius
DOI:10.1021/jacs.8b00868
日期:2018.3.14
The highly enantioselective [5 + 2] annulation of enals with vinylethylene carbonates through a cooperative N-heterocyclic carbene (NHC)/Pd catalytic system is reported. The use of a bidentate phosphine ligand was crucial to prevent coordination of the NHC organocatalyst to the active Pd catalyst. The complementary and matched combination of the chiral NHC catalyst and chiral phosphine ligand promotes