Iridium-Catalyzed Kinetic Asymmetric Transformations of Racemic Allylic Benzoates
摘要:
Versatile methods for iridium-catalyzed, kinetic asymmetric substitution of racemic, branched allylic esters are reported. These reactions occur with a variety of aliphatic, aryl, and heteroaryl allylic benzoates to form the corresponding allylic substitution products in high yields (74-96%) with good to excellent enantioselectivity (84-98% ee) with a scope that encompasses a range of anionic carbon and heteroatom nucleophiles. These kinetic asymmetric processes occur with distinct stereochemical courses for racemic aliphatic and aromatic allylic benzoates, and the high reactivity of branched allylic benzoates enables enantioselective allylic substitutions that are slow or poorly selective with linear allylic electrophiles.
Copper-catalyzed enantioselective allylic oxidation of acyclic olefins
作者:Bo Zhang、Shou-Fei Zhu、Qi-Lin Zhou
DOI:10.1016/j.tetlet.2013.03.046
日期:2013.5
copper-catalyzed asymmetricallylicoxidation of acyclic olefins has been developed. By using the complexes of copper and chiral spiro bisoxazoline ligands as catalysts, the oxidation of various acyclic olefins was accomplished with excellent regioselectivity (>20:1 in most cases) and up to 67% ee under mild reaction conditions, which represents one of the best results for the enantioselective allylic oxidation
A Pd-catalyzed multicomponent cross-coupling of allyl esters with alkyl bromides to synthesize allylic sulfones by using K2S2O5 as a connector is first reported. The reaction displays a broad range of substrate generality along with excellent functional group compatibility and produces the products with high regioselectivity (only E). Furthermore, the biologically active molecules with a late-stage
首次报道了以K 2 S 2 O 5作为连接剂,Pd催化烯丙基酯与烷基溴多组分交叉偶联合成烯丙基砜。该反应显示出广泛的底物通用性以及优异的官能团兼容性,并产生具有高区域选择性的产物(仅E)。此外,经过后期修饰的生物活性分子,包括阿司匹林、薄荷醇、冰片、雌酮等,也与多组分交叉偶联反应高度相容。机理研究表明SO 2插入C-Pd 键的过程参与了这一转变。