Abstract: A method of making an endoperoxide from a diene and oxygen in the presence of a photocatalyst having an excited state lifetime of at least 100 nanoseconds, the endoperoxide being represented by the formula: where R1 is an aryl substituted with at least one group selected from the group consisting of alkoxy, hydroxyl, halogen, carbamate, sulfonamide, silyloxy, amide, and combinations thereof or a substituted or unsubstituted heteroaryl, R2 is hydrogen, alkyl, alkynyl, or aryl, R3 is hydrogen, alkyl, alkynyl, or aryl, R4 is alkynyl or aryl, R5 is hydrogen or a substituent, R6 is hydrogen or a substituent, and A1, A2, and A3 are the same or different atoms and form a divalent group that combines with the two carbon atoms of the endoperoxide ring to form a saturated or unsaturated, substituted or unsubstituted ring system of a size of from five to six atoms.

Abstract: A method of making an endoperoxide from a diene and oxygen in the presence of a photocatalyst having an excited state lifetime of at least 100 nanoseconds, the endoperoxide being represented by the formula: where R1 is an aryl substituted with at least one group selected from the group consisting of alkoxy, hydroxyl, halogen, carbamate, sulfonamide, silyloxy, amide, and combinations thereof or a substituted or unsubstituted heteroaryl, R2 is hydrogen, alkyl, alkynyl, or aryl, R3 is hydrogen, alkyl, alkynyl, or aryl, R4 is alkynyl or aryl, R5 is hydrogen or a substituent, R6 is hydrogen or a substituent, and A1, A2, and A3 are the same or different atoms and form a divalent group that combines with the two carbon atoms of the endoperoxide ring to form a saturated or unsaturated, substituted or unsubstituted ring system of a size of from five to six atoms.