Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States.
Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States.
J Am Chem Soc. 2019 Sep 25;141(38):15024-15028. doi: 10.1021/jacs.9b08659. Epub 2019 Sep 10.
Direct enantioselective α-alkylation of 2-alkylpyridines provides access to chiral pyridines via an operationally simple protocol that obviates the need for prefunctionalization or preactivation of the substrate. The alkylation is accomplished using chiral lithium amides as noncovalent stereodirecting auxiliaries. Crystallographic and solution NMR studies provide insight into the structure of well-defined chiral aggregates in which a lithium amide reagent directs asymmetric alkylation.
通过操作简单的方案,直接对 2-烷基吡啶进行对映选择性α-烷基化,为手性吡啶的合成提供了一种途径,该方案避免了底物的预官能化或预活化。通过使用手性锂酰胺作为非共价立体定向助剂来实现烷基化。晶体学和溶液 NMR 研究提供了对定义明确的手性聚集体结构的深入了解,其中手性锂酰胺试剂指导不对称烷基化反应。