Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.
J Am Chem Soc. 2011 May 4;133(17):6541-4. doi: 10.1021/ja2015586. Epub 2011 Apr 8.
This communication describes a new method for the Pd/polyoxometalate-catalyzed aerobic olefination of unactivated sp(3) C-H bonds. Nitrogen heterocycles serve as directing groups, and air is used as the terminal oxidant. The products undergo reversible intramolecular Michael addition, which protects the monoalkenylated product from overfunctionalization. Hydrogenation of the Michael adducts provides access to bicyclic nitrogen-containing scaffolds that are prevalent in alkaloid natural products. Additionally, the cationic Michael adducts undergo facile elimination to release α,β-unsaturated olefins, which can be further elaborated via C-C and C-heteroatom bond-forming reactions.
本文描述了一种新的方法，用于 Pd/多金属氧酸盐催化的未活化 sp(3) C-H 键的有氧烯烃化反应。氮杂环作为导向基团，空气作为末端氧化剂。产物经历可逆的分子内迈克尔加成反应，从而保护单烯丙基化产物免受过度官能化。迈克尔加成产物的加氢反应提供了获得在生物碱天然产物中普遍存在的双环含氮支架的途径。此外，阳离子迈克尔加成物易于消除释放α,β-不饱和烯烃，这些烯烃可以通过 C-C 和 C-杂原子键形成反应进一步进行修饰。
