Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 197
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 197
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 271
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1075
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3195
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 597
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 511
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 317
Function: require_once
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Optically active α-aminophosphonic acids are unique analogues of α-amino acids, and numerous synthetic methods have been developed. Herein, we present a highly diastereoselective α-azidation approach to the CAMDOL-derived phosphonates, enabling ready access to 27 diverse α-azidophosphonates with defined chirality in up to 85% yield and more than 99:1 dr. Late-stage transformations through the Staudinger reaction or click reaction efficiently delivered the related pharmacological α-aminophosphonic acids or the unique α-triazolylphosphonate derivative, respectively. This CAMDOL-induced asymmetric architecture of the P-adjacent carbon chiral center exhibited comparable advantages over known induction methods with high stereoselectivity, easy manipulability, and broad compatibility.
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http://dx.doi.org/10.1021/acs.orglett.5c03243 | DOI Listing |