Radical dearomatization of benzene leading to phenanthridine and phenanthridinone derivatives related to (±)-pancratistatin
摘要:
The synthesis of the phenanthridinone nucleus common to the Amaryllidaceae series of natural products is achieved by a sequence involving tributylstannane-mediated, benzeneselenol-catalyzed addition of ortho-nitrogen functionalized aryl radicals to benzene, yielding aryl-substituted cyclohexadienes. These cyclohexadienes may be manipulated by oxidative ring closure sequences to generate functionalized phenanthridines. Beginning from 2-hydroxy-6-iodopiperonic acid a key intermediate in the Danishefsky synthesis of (+/-)-pancratistatin is achieved in two steps. (c) 2006 Elsevier Ltd. All rights reserved.
Intramolecular Trapping of Allenylzincs by Carbonyl Groups
作者:Suribabu Jammi、Julien Maury、Jean-Simon Suppo、Michèle P. Bertrand、Laurence Feray
DOI:10.1021/jo4022293
日期:2013.12.20
Allenylzinc formed via oxygen-promoted zinc/iodineexchangebetween propargyl iodides and diethylzinc can be trapped by intramolecular reaction with various electrophiles such as aldehydes, ketones, esters, carbamates, and imides. Potentially useful building blocks were obtained in high yields.