Intramolecular Rhodium-Catalyzed [2+2+2] Cyclizations of Diynes with Enones
作者:Amanda L. Jones、John K. Snyder
DOI:10.1021/jo9001678
日期:2009.4.3
The Rh(I)-catalyzed inter- and intramolecular [2+2+2] cyclization of diynes with alpha,beta-unsaturated enones proceeds with microwave promotion in good yields. This chemistry was applied to the synthesis of (-)-alcyopterosin I.
Aza Diels–Alder Reactions of Nitriles, <i>N</i>,<i>N</i>-Dimethylhydrazones, and Oximino Ethers. Application in Formal [2 + 2 + 2] Cycloadditions for the Synthesis of Pyridines
作者:Philip J. Hamzik、Anne-Sophie Goutierre、Takeo Sakai、Rick L. Danheiser
DOI:10.1021/acs.joc.7b02503
日期:2017.12.15
Metal-free, formal [2 + 2 + 2] cycloaddition strategies for the synthesis of polycyclic pyridine derivatives are described. The overall transformation proceeds via a two-stage pericyclic cascade mechanism. In the first step, an intramolecular propargylic enereaction generates a vinylallene that is necessarily locked in the s-cis conformation. This vinylallene exhibits exceptional reactivity as a Diels–Alder