An enantioselective synthesis of 3,4-benzo-5-oxacephams was written by Koziol, Anna;Frelek, Jadwiga;Woznica, Magdalena;Furman, Bartlomiej;Chmielewski, Marek. And the article was included in European Journal of Organic Chemistry in 2009.COA of Formula: C40H26O2 The following contents are mentioned in the article:
The title compounds, e.g., I, represent an interesting group of 1-lactam antibiotics and active inhibitors of β-lactamase enzymes. All these compounds have one structural feature in common, an alkoxy fragment located at C4 of the azetidin-2-one ring. The most common strategy for the synthesis of 4-alkoxyazetidinones involves intramol. nucleophilic substitution at C4 that leads to ring closure. Such a displacement proceeds via the flat intermediate that supposedly has the structure of a mesomeric acyl ammonium cation. We herein report a novel and enantioselective chiral Lewis acid-mediated cyclization that affords the corresponding 5-oxacepham with excellent enantioselectivity and chem. yields of up to 50%. This may suggest that the high asym. induction is a result of a kinetic resolution of the initially formed racemic oxacepham. This study involved multiple reactions and reactants, such as (R)-[1,3′:1′,1”:3”,1”’-Quaternaphthalene]-2′,2”-diol (cas: 851615-07-1COA of Formula: C40H26O2).
(R)-[1,3′:1′,1”:3”,1”’-Quaternaphthalene]-2′,2”-diol (cas: 851615-07-1) belongs to alcohols. Alkyl halides are often synthesized from alcohols, in effect substituting a halogen atom for the hydroxyl group. Secondary alcohols are easily oxidized without breaking carbon-carbon bonds only as far as the ketone stage. No further oxidation is seen except under very stringent conditions.COA of Formula: C40H26O2
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts