through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
Palladium-catalyzed carbocyclization–cross-coupling reactions of two different allenic moieties: synthesis of 3-(buta-1,3-dienyl) carbazoles and mechanistic insights
作者:Benito Alcaide、Pedro Almendros、José M. Alonso、Israel Fernández
DOI:10.1039/c2cc32015k
日期:——
A palladium-catalyzed chemo-, regio- and stereoselective carbocyclizationâcross-coupling sequence of two different α-allenols to afford 3-(E-buta-1,3-dienyl) carbazoles is reported.
A highly efficient and stereoselective method for the synthesis of (1Z)‐1,2‐dihalo‐3‐vinyl‐1,3‐dienes featuring palladium‐catalyzed coupling of haloalkynes and 2,3‐butadienyl acetates was developed. The resulting products were smoothly converted into cis‐1,2‐dihalostyrene derivatives using the Diels–Alder/aromatization sequence.
Synergistic Cu/Pd‐Catalyzed Asymmetric Allenylic Alkylation of Azomethine Ylides for the Construction of α‐Allene‐Substituted Nonproteinogenic α‐Amino Acids
作者:Hua‐Chao Liu、Yuan‐Zheng Hu、Zuo‐Fei Wang、Hai‐Yan Tao、Chun‐Jiang Wang
DOI:10.1002/chem.201901046
日期:——
This dual catalytic system possesses good substrate compatibility, delivering a diverse array of nonproteinogenic α‐allenylic α‐mono‐ or α,α‐disubstituted α‐aminoacids (α‐AAs) with high yields and generally excellent enantioselectivities. Furthermore, the scalability and practicability of the current synthetic protocol were proven by performing gram‐scale reactions and by the first catalytic asymmetric
Construction of Acyclic All‐Carbon Quaternary Stereocenters and 1,3‐Nonadjacent Stereoelements via Organo/Metal Dual Catalyzed Asymmetric Allenylic Substitution of Aldehydes
A novel synthetic strategy for the asymmetric allenylic substitution of aldehydes, which enables the construction of allene-containing acyclic all-carbonquaternarystereocenters and 1,3-nonadjacent stereoelements, has been reported.