The intramolecular cobalt-mediated reaction of α,ω-allenynes 8 leads to bicyclic dienones 10 and α-alkylidenecyclopentenones 11; regioselectivity depends on the substitution pattern of the allenic moiety.
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
γ-Allenic α-amino acids can be obtained by a three-step sequence from the phosphates of α-allenic alcohols: i) palladium-catalyzed alkylation of a Schiff base derived from glycine ester by these phosphates, ii) acidic hydrolysis of the imine functionality, and iii) saponification of the resulting amino esters.
Rearrangement Reactions of 1,1-Divinyl-2-phenylcyclopropanes
作者:E. Ben Hay、Hanmo Zhang、Dennis P. Curran
DOI:10.1021/ja510608u
日期:2015.1.14
1,1-Divinyl-2-phenylcyclopropanes are entry points to a rich area of rearrangement chemistry. With N,N-diallyl amide substrates, tandem radical cyclizations can be initiated at room temperature. Warming provides products of pure thermal rearrangements with acids, ester, and amides. These isomerizations give vinylcyclopentenes resulting from divinylcyclopropane rearrangements and more deeply rearranged