Photochemical reactivity of keto imino ethers. VI. Type I rearrangement and (2 + 2) photocycloaddition to the carbon-nitrogen double bond of 2-oxazolin-4-ones

Total Synthesis of Dimethyl Sulfomycinamate

“…The model studies started from the known oxazolone 12 , which was secured by a literature procedure ).…”

Di-tert-butyl nitroxide quenching of the photoaddition of olefins to the carbon-nitrogen double bond of 3-ethoxyisoindolenone

“…Substituent effects on the photoreactivity of a structurally related molecule, 2-phenyl-2-oxazolin-4-one, implicate a , * configuration for the reactive state in [2 + 2] photocycloaddition to its carbon-nitrogen double bond. 16 We suspect that the reactive triplet state of 1 results from a vibronic coupling of , * and , * states of similar energy.34 Alternatively equilibrating , * and , * states could be involved.…”

“…15 Quenching experiments indicate that the reactions occur from a triplet state, and substituent effects in a related system suggest that cycloaddition probably occurs from a state with , * configuration. 16 To explain the stereochemistry for the [2 + 2]-cycloaddition and ene reactions and the results of the quenching experiments, we proposed a 3-ethoxyisoindolenone-olefin, triplet, exciplex intermediate which gives ene products with partial or complete stereospecificity and a biradical which subsequently gives ene products and [2 + 2] cycloadducts stereorandomly. We then surmised that if DTBN were able to quench the proposed triplet exciplexes in the [2 + 2]-photocycloaddition reactions of 2-cyclohexenones, it might also be able to quench the proposed triplet exciplex in our photoaddition reactions.…”

Review on Asymmetric Catalysis Employing 5H‐Oxazol‐4‐Ones as α‐Hydroxy Carboxylic Acid Surrogates

“…Substituted α‐bromoacylhalide undergoes the condensation reaction with aryl amide to afford diamide intermediate. The diamide is further converted into the oxalactim via cyclization under microwave irradiation [22] …”