Transition-Metal-Free [4+3]-Cycloaddition of ortho-Quinone Methides and Isomünchnones: Catalytic and Diastereoselective Assembly of Oxa-bridged Oxazocine Scaffolds.
Heather LamZafar QureshiMarcus WegmannMark LautensPublished in: Angewandte Chemie (International ed. in English) (2018)
Cycloadditions are powerful processes to synthesize complex polycyclic scaffolds. Herein, we disclose a [4+3]-cycloaddition between an in situ generated ortho-quinone methide and an isomünchnone to yield oxa-bridged oxazocine cores, generating N2 and H2 O as the sole by-products. Using only catalytic amounts of camphorsulfonic acid, it is possible to generate both reactive intermediates in one step, eliminating the need for rhodium catalysts generally employed for isomünchnone formation. Spectroscopic data and X-ray crystallography indicate the formation of the syn diastereomer, with the main side-product arising from a hydrate participating in a competing [4+2]-cycloaddition pathway.
Keyphrases
- transition metal
- acinetobacter baumannii
- klebsiella pneumoniae
- tissue engineering
- multidrug resistant
- high resolution
- molecular docking
- drug resistant
- electronic health record
- crystal structure
- pseudomonas aeruginosa
- escherichia coli
- highly efficient
- magnetic resonance imaging
- dual energy
- cystic fibrosis
- mass spectrometry