Oxidative cyclization of tertiary pentenol derivatives forming 2,5,5-trisubstituted THF rings and the total synthesis of cyclocapitelline
作者:Geoffrey A. Phillips、Cory Palmer、Andrew C. Stevens、Mathew L. Piotrowski、Daryl S.R. Dekruyf、Brian L. Pagenkopf
DOI:10.1016/j.tetlet.2015.09.064
日期:2015.10
The synthesis of 2,5,5-trisubstituted tetrahydrofuran rings was accomplished via the Mukaiyama aerobic oxidativecyclization of tertiary 5-pentenols employing the Co(nmp)2 catalyst. A variety of THFs were formed in moderate to good yield and diastereoselectivity. The method developed herein was successfully applied to an enantioselective total synthesis of cyclocapitelline.
Intramolecular Polar [4<sup>⊕</sup>+2] Cycloadditions of Aryl-1-aza-2-azoniaallene Salts: Unprecedented Reactivity Leading to Polycyclic Protonated Azomethine Imines
作者:Daniel A. Bercovici、Jodi M. Ogilvie、Nikolay Tsvetkov、Matthias Brewer
DOI:10.1002/anie.201306553
日期:2013.12.9
Charged up: In the first example of the title salts undergoing a [4⊕+2] cycloaddition reaction, the azo bond and one aromatic π bond make up the 4π component. This reaction appears to be concerted and provides high yields of protonatedazomethineimine products. Substituted alkenes provided products containing all‐carbon or nitrogen‐bearing quaternary centers in high yield.