Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Symmetrical biheteroaryl compounds, such as bypyridines and bipyrazoles, are important ligands in transition-metal catalysis. They also serve as synthetic precursors of photo catalysts/sensitizers, bioactive agents, and energetic materials. To facilitate the concise synthesis of these useful structures, an efficient Pd-catalyzed homocoupling of heteroaryl bromides has been successfully established using the electron-rich and sterically hindered monophosphorus ligand BIDIME. The coupling protocol features a tandem Miyaura borylation/Suzuki coupling sequence and exhibits unprecedented tolerance of a wide range of heteroaryl bromides, providing a series of symmetrical biheteroaryls in moderate to good yields. Notably, the use of the corresponding polymeric ligand, PolyBIDIME, enabled the recycling of a palladium catalyst, demonstrating the potential of the homocoupling in practical applications.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1021/acs.orglett.4c03060 | DOI Listing |
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