Catalytic, Enantioselective Alkylation of α-Imino Esters: The Synthesis of Nonnatural α-Amino Acid Derivatives
作者:Dana Ferraris、Brandon Young、Christopher Cox、Travis Dudding、William J. Drury、Lev Ryzhkov、Andrew E. Taggi、Thomas Lectka
DOI:10.1021/ja016838j
日期:2002.1.1
Methodology for the practical synthesis of nonnatural amino acids has been developed through the catalytic, asymmetric alkylation of α-imino esters and N,O-acetals by enol silanes, ketene acetals, alkenes, and allylsilanes using chiral transition metal-phosphine complexes as catalysts (1−5 mol %). The alkylation products, which are prepared with high enantioselectivity (up to 99% ee) and diastereoselectivity
Yb(OTf)(3) with TMSCl or TMSOTf catalyzed an imino enereaction. The reaction of N-tosylbenzaldimine (1) with alpha-methylstyrene (2) proceeded smoothly to give homoallylic amine 3 in the presence of a catalytic amount of Yb(OTf)(3) and TMSCl. This catalytic system was successfully applied to the imino enereactions of various aldimines with alkenes. This new imino enereaction provides a unique method for
作者:Xi‐Jia Liu、Chao Zheng、Yi‐Han Yang、Shicheng Jin、Shu‐Li You
DOI:10.1002/anie.201904156
日期:2019.7.29
Described herein is an asymmetric allylic aromatization (AAAr) strategy that employs readily accessible equivalents of benzylic nucleophiles in iridium‐catalyzed allylic substitution reactions with the concomitant formation of aromatic rings by aromatization. The optimized reaction conditions involving a catalyst derived from a commercially available iridium precursor and the Carreira ligand are compatible
corresponding allyl halides in high yield, including allyl bromide, chloride, iodide and fluoride, is described. A remarkable feature of Yb(OTf)3–TMSCl-catalyzed halogenation is that, unlike conventional radical halogenation with N-halosuccinimides, the reaction discriminates between the allylic and benzylic positions. The reaction occurs selectively at the allylic position to give allylic halides, but