Szwnmary. The reaction of photogenerated singlet oxygen with a-and P-pinenes has bcen carefully re-examined. cr-Pinene almost exclusively (99.3 % yield) furnishes trans-3-hydroperoxy-pin-2 (10)-ene. However, detectable amounts of the three other possible products are also found, viz., cis-3-hydroperoxypin-2 (10)-ene (-0.8%), and cis-and tvuns-2-hydroperoxypin-3 (4)-ene (-0.04%). P-Pinene gives 99.9% of 10-hydroperoxypin-2 (3)-ene and a trace (-0.01%) of norpinan-2-one. Rates of reaction and product composition are treated by modal analysis and reflect the operation of steric and stercoelcctronic factors in a reactant-like transition state.
Suvwnary. The reaction of singlet oxygen with 2-phenylnorbornene (1) in aprotic solvents gives 3-formylcyclopentyl phenyl ketone (2) (10%) and uncharacterized polymer (90%). When methanol is used as solvent, endo-2-phenyl-exo-2-methoxy-ex~-3-hydropcrox~norbornane (4) and endo-2-(a&-1 ', 4'-epidioxy-5', 6'-epoxycyclohex-2'-enyl)-exo-2,3-epoxynorbornane (6 and 7) are obtained in addition to 2. Triplet oxygen with 1 gave 2, eizdo-2-phenyl-exo-2,3-epoxynorbornane (S), and the trimer 9 or 10 of exo-2,3-epidioxy-endo-Z-phenylnorbornane. With protic solvents the amount of epoxide increased at the expense of trimer. The singlet and triplet oxygen reactions are discussed in the light of possible intermediates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.