Rh(II) acetate catalyzed cyclopropanation of styrenes with enaldiazo esters: diastereoselective synthesis of enal-cyclopropanes
摘要:
An efficient Rh(II) acetate catalyzed highly diastereoselective cyclopropanation of styrenes with enaldiazo esters has been developed (up to >95:5 dr and 62-82% yield). The reaction is proposed to involve diacceptor electrophilic rhodium enalcarbenoids and constitutes the first direct synthesis of enal-cyclo-propanes with an all carbon 7-quaternary stereocenter. (C) 2014 Elsevier Ltd. All rights reserved.
electrophilic rhodium enalcarbenoid which results from rhodium(II)‐catalyzeddecomposition of a new class of enaldiazo compounds. The synthetic utility of these enalcarbenoids has been successfully demonstrated in the first transition‐metal‐catalyzed [4+2] benzannulation of pyrroles, thus leading to substituted indoles. The new benzannulation has been applied to the efficientsynthesis of the natural