An oxidative dearomatization of phenol followed by a dynamic kinetic (DyKat) ketalization/oxa-Michael addition cascade using cinchona alkaloid-based chiral bifunctional amino-squaramide catalysts is reported. A broad array of sterically hindered [5,5]-spiroketals attached to a cyclohexadienone moiety in spiro-fashion is synthesized in an enantiopure form. Further, the methodology was optimized and
An Oxidative Prins-Pinacol Tandem Process and its Application to the synthesis of (−)-Platensimycin
作者:Marc-André Beaulieu、Cyrille Sabot、Nabil Achache、Kimiaka C. Guérard、Sylvain Canesi
DOI:10.1002/chem.201001813
日期:——
Center stage: An oxidative Prins–pinacol tandemprocess mediated by a hypervalent iodine reagent has been accomplished. The strategy allows rapid access to highly functionalized spirocyclic cores (see scheme) present in many natural products. A first application to the formal synthesis of (−)‐platensimycin has been achieved.
Transition Metal Free C–N Bond Forming Dearomatizations and Aryl C–H Aminations by in Situ Release of a Hydroxylamine-Based Aminating Agent
作者:Joshua J. Farndon、Xiaofeng Ma、John F. Bower
DOI:10.1021/jacs.7b07830
日期:2017.10.11
We outline a simple protocol that accesses directly unprotected secondary amines by intramolecular C-N bond forming dearomatization or aryl C-H amination. The method is dependent on the generation of a potent electrophilic aminating agent released by in situ deprotection of O-Ts activated N-Boc hydroxylamines.