[structure: see text] The stereocontrolled synthesis of pyridooxazinones by Mg(OTf)2-promoted epoxide ring-opening with use of chiral pipecolates as nucleophiles is described. Pyridooxazinone products derived from azido-epoxides can be further rearranged to seven-membered pyridodiazepinones by azide reduction. The sequence of functional group interconversions generates diversity through topological and stereochemical variation.
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http://dx.doi.org/10.1021/ol070321g | DOI Listing |
Nat Chem
January 2025
Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science and Technology, Shenzhen, China.
The substitution of an aromatic ring with a C(sp)-rich bicyclic hydrocarbon, known as bioisosteric replacement, plays a crucial role in modern drug discovery. Substituted bicyclo[1.1.
View Article and Find Full Text PDFJ Org Chem
January 2025
Applied Chemistry and Chemical Engineering, Graduate School of Engineering, Kogakuin University, Nakano 2665-1, Hachioji, Tokyo 192-0015, Japan.
The cascade aza-Prins/Friedel-Crafts reaction of homocinnamyloxycarbamate with electron-rich aromatic aldehydes has been successfully established. Most of the aromatic aldehydes react with the carbamate stereoselectively to generate -hydroindeno-1,2-oxazinanes. However, the cascade reactions of benzaldehydes bearing two methoxy groups at the -positions exhibit a unique stereochemical profile.
View Article and Find Full Text PDFChemistry
December 2024
Organocatalysis Research Group, Institute of Organic Chemistry, HUN-REN Research Centre for Natural Sciences, 2. Magyar tudósok krt., H-1117, Budapest, Hungary.
A concise, bioinspired, and enantioselective synthesis of (-)-hunterine A, an odd 6/7/6/6/5 pentacyclic natural product, is described. The key step in the synthesis of this complex structure is an interim-template directed 6-exo selective epoxide ring-opening reaction, which is interwoven with a hydrolysis step of the indolenine hemiaminal template to create the unusual 7-membered azepine bridge motif. Our work not only refines the previously proposed biogenetic pathway, but also reveals the possible stereochemical prerequisite of the unique skeletal rearrangement, which provides a vantage point for understanding how (-)-hunterine A is likely to be generated in nature.
View Article and Find Full Text PDFChem Asian J
January 2024
Program on Chemical Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Center of Excellence on Environmental Health and Toxicology (EHT), Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation, 906 Kamphaeng Phet 6, Talat Bang Khen, Lak Si, Bangkok, 10210, Thailand.
Herein, we report the unusual skeletal rearrangement of spiro[4.5]decadienone to benzoxepane. In particular, Lewis acid-promoted epoxide-opening ipso-cyclization of aryl epoxides afforded spiro[4.
View Article and Find Full Text PDFChemMedChem
July 2023
Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, 27272, United Arab Emirates.
Stereochemical and skeletal complexity are particularly important vis-à-vis the cross-talks between a small molecule and a complementary active site of a biological target. This intricate harmony is known to increase selectivity, reduce toxicity, and increase the success rate in clinical trials. Therefore, the development of novel strategies for establishing underrepresented chemical space that is rich in stereochemical and skeletal diversity is an important milestone in a drug discovery campaign.
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