Approach to highly functionalized oxazolones by a Pd-catalyzed cyclization of N-alkynyl tert-butyloxycarbamates
摘要:
A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C-Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag2CO3 to generate 3,4,5-trisubstituted oxazolones, respectively. (C) 2012 Elsevier Ltd. All rights reserved.
A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C-Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag2CO3 to generate 3,4,5-trisubstituted oxazolones, respectively. (C) 2012 Elsevier Ltd. All rights reserved.
Intramolecular (3+2) cycloaddition reactions involving benzyne and ynamides as three-atom components have been accomplished through the utilization of benzyne precursors having a linking functionality. The ambivalent nature of the intermediate indolium ylide, which exhibits both nucleophilic and electrophilic properties at its C2 atom, is thus brought to light in this approach.