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
Michael adducts of imines of α-aminoacidesters are converted into a mixture of two stereoisomeric pyrrolidines by benzyltrimethylammonium methoxide (BTAM) apparently by a 5-endo-trigcyclisation.
Copper(II)salen catalysed, asymmetric synthesis of α,α-disubstituted amino acids
作者:Yuri N Belokon、Devayani Bhave、Daniela D'Addario、Elisabetta Groaz、Michael North、Valeria Tagliazucca
DOI:10.1016/j.tet.2003.12.031
日期:2004.2
Cu(salen) complex 1 was found to be a versatile catalyst for the asymmetric alkylation of a range of enolates derived from α-amino acids, leading to α,α-disubstituted amino acids. The enantioselectivity of the process decreases as the size of the amino acid sidechain increases, but functionalized amino acids such as allylglycine and aspartic acid are substrates for the process. Benzylic bromides are